Retro Review: Casio BF-80

Retro Review:   Casio BF-80

A folding calculator with easy-to-calculate finance prompts.  

Quick Facts

Model:  BF-80  (Easy Banker Financial)

Company:  Casio

Years:  1985 (production run is probably the late 1980s)

Type:  Finance

Batteries: 1 x CR-2016

Operating Modes:  Chain

Number of Registers: 2 User registers:  M,  Kin/Kout 

Display:  2 lines

Features

The BF-80 is a dual-leaf calculator.  On the left side, you have a regular four-function calculator, including memory functions, percent, and the square root function.

On the right side is where all the financial functions the BF-80 are located:

[ Kin ]/[ Kout ]:  The BF-80's other user memory register.  Unlike register M, there is no register arithmetic.

[ HMS ]/[ <HMS ]:  Convert decimal to/from hours-minutes-seconds.  Use the [ HMS ] key to enter parts of time.  

Example:  Add 3.5 hours to 11:30:00

11 [ HMS ] 30 [ HMS ] [ + ] 3.5 [ = ] 

Result:  15°0°0 (15:00:00)

[ DATE ]:  The date key leads two of my favorite functions of all time:  days between dates and calculating a future date.   The format is yy - mm - dd  (no dashes for 21st century dates).  Years are entered as four digits, from 1901 to 2099.  

For most, if not all, calculators, the cash flow convention is not used.  

INST-FV:  Calculates the future value of an annuity.  Interest rate is entered as periodical rate. Note that deposits are made at the beginning of each period (annuity due).  The INST indicator turns on. 

Example:  I pay $500 a month in an account that pays 5% interest for 10 years.

[ INST FV ]   (INST indicator is on)

PMT?  500 [ ENTER ]

i%?  5 [ ÷ ] 12 [ = ] [ ENTER ] 

n?  10 [ ÷ ]  12 [ = ] [ ENTER ]

FV= 77964.641

Pressing [ INT ] gives the interest earned:  17964.641.

CMPD-FV:  Calculates the future value of a lump sum (present value).  The CMPD indicator turns on, and INT gives the accumulated interest.

CMPD-PV:  Calculates the present value of a future lump sum (future value).  The CMPD indicator turns on, and INT gives the accumulated interest.  

Both CMPD calculations use this equation:

FV = PV * (1 + i%)^n

LOAN-PMT:  Calculates the monthly payment of a loan due at the end of each month.  The loan is to paid without a balloon payment.  The LOAN indicator turns on.

PV?:  amount to be financed

i%?:  annual interest rate

m?:  number of monthly payments

Example:  What is the monthly payment of $8,293.00 loan with 6% interest over 6 years?

[ LOAN PMT ] (LOAN indicator is on)

PV? 8293 [ ENTER ]

i%?  6 [ ENTER ] (no dividing by 12 in LOAN mode)

m? 6 [ × ] 12 [ = ] [ ENTER ] (still enter the number of months)

PMT = 137.43896

Pressing [ INT ] gives the accumulated interest paid on the loan:  -1602.6051

LOAN-BNS:  Calculates the bonus payment of a separate (side) loan given the number of bonus payments and it's cycle.

k = number of bonus payments

d = number of months to the first bonus payment

PV = bonus loan amount

i% = annual interest rate of the bonus loan

Example:  What is the payment of a bonus loan of $4,412.00 with 3% interest.  The firs bonus cycle is every 3 months from the loan date, with 15 bonus payments.

[ LOAN BNS ]  (LOAN indicator is on)

PV?  4412 [ ENTER ]

i%?  3 [ ENTER ]  (annual rate, like LOAN-PMT)

k?  15 [ ENTER ] (number of bonus payments)

d?  3 [ ENTER ] (number of months prior to the first bonus payment)

BNS = 328.21123

Pressing [ INT ] gives the accumulated interest:  -511.16857

I guess that this is for loans where payments are due every few months instead of every month.  

The Percent Key

The percent key on the BF-80 works like most Casio calculators with a percent key.   

To add a percent:  n [ × ] p [ % ] [ + ]

To subtract a percent:  n [ × ] p [ % ] [ - ]

To find a percent ratio:  part [ ÷ ] whole [ % ]

Percent change:  new [ - ] old [ % ]

A Neat Calculator - An 1980s Version of a Smartphone App 

For it's time, the BF-80 offers calculator with quick, prompting calculations for the on-the-go business and finance student or profession.  Today, in the 2020s, the calculator of this time definitely would  be a smartphone app.  

Surprisingly buying a BF-80 was incredibly reasonable.   

Coming up:

July 11 - July 15, 2022:  TI-58 and TI-59 Week

Next Regular Blog:  July 10, 2022, then  July 23, 2022

Eddie

All original content copyright, © 2011-2022.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Retro Review: Texas Instruments BA-Solar

Retro Review: Texas Instruments BA-Solar

Finance + Solar + 1980s

Quick Facts

Model:  BA-Solar

Company:  Texas Instruments

Years:  1986 - 1990s; a refresh , BA-35 SOLAR was produced 1996-2000s

Type:  Finance

Batteries: Solar 

Operating Modes:  Chain

Number of Registers: 1, |MEM|

Display:  1 line, 10 digits

Features

The [ MODE ] key is used to toggle between three modes:

FIN Mode:  Time Value of Money  (FIN indicator)

N:  number of payments

%i:  periodic interest rate

PV:  present value

PMT:  payment

FV:  future value

The current cash flow convention is not used, instead the following equation is (I think) used in solving time value of money calculations: 

PV = FV *  SPPV + PMT * USPV

SPPV = single present value factor

USPV = present value annuity factor

We also have amortization functions:

BAL:  balance after any payment

I/P:  interest and principal at any payment

payment_1 P1/P2 payment_2 I/P:  cumulative interest and principal

There are ×12 and ÷12 aids, but we still have to press [ N ] and [ %i ] to register the values, they are not automatic.  

STAT Mode:  Statistics  (STAT indicator)

The BA-SOLAR (and the later BA-35 SOLAR) has both single variable statistics and linear regression.

In linear regression, use the [x<>y] key to change between x and y.   The key will also be used to switch between results.  

Prediction values can be calculated with x' and y'.

The equation used for linear regression is y = a*x + b,  a = slope, b = intercept.

Profit Mode (no indicator)

The profit mode makes the following solver available:

CST:  cost

SEL:  sell

MAR:  margin

MU:  markup

Functions Available in All Modes

Percent Calculations (%):

Add %:  x [ + ] y [ % ] [ = ]

Subtract %:  x [ - ] y [ % ] [ = ]

Multiply %:  x [ × ] y [ % ] [ = ]

Percent Ratio:  part [ ÷ ] whole [ % ] [ = ]

Percent Change:  new [ 2nd ] ( ⊿% ) old [ = ]

rate >EFF payments/year:  convert to effective rate

rate >APR payments/year:  convert to APR/nominal rate

Mathematics:

Natural logarithm and antilogarithm:  ln x, ^x

Square and square root

Power

Reciprocal

Final Thoughts

This is a great basic financial calculator.  I have both the BA-SOLAR and BA-35 SOLAR.   To be honest, I like the keyboard of the original BA-SOLAR better, the keys feel a bit more solid and responsive.  Even though they are no longer in production, the BA-SOLAR is still reasonably available on sites such as eBay and other online stores.  

Source:

Woerner, Joerg.  "Texas Instruments BA-SOLAR"  Last Updated December 5, 2001.   http://www.datamath.org/Sci/Modern/BA-SOLAR.htm   Retrieved May 19, 2022.

Eddie

All original content copyright, © 2011-2022.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Retro Review: TI Investment Analyst

 Retro Review:   TI Investment Analyst

Today's review will be on a specialized calculator that had a very short life in the market:  the Texas Instruments Investment Analyst.  

Quick Facts:

Model:  Investment Analyst

Company:  Texas Instruments

Years:  1979-1980

Type:  Specialized Finance

Batteries: 2 x LR44

Operating Mode:  Chain

Features: Stocks, Bonds, Options

*  The [CIF] key:  which calculates (1 + i%)^n.  Used in time value of money calculations.

* Days between Dates allowing for four digit years.  The manual states that this function is accurate for the range March 1, 1900 to February 28, 2100.  The date format is mmdd.yyyy.  Example:  March 28, 2022 is 328.2022.

* The [ 2nd ] (Sec Typ) sets the security type mode.  

Stocks (Security Type A)  

We can solve for the purchase price (buy), selling price (sell), and yield.   Variables include:

**  the number of days until the first dividend is paid (B→P), the number of days from 

**  the last dividend until the stock is sold (P←S)

**  capital gains tax rate and income tax rate 

**  commissions rate when the stock is bought and sold

**  dividends, and dividend growth rate

**  The Investment Analyst has two modes for stocks:  annual yield and ownership period yield.  The latter mode is simpler.  

Bonds (Security Type B)

The keys to operate calculations for bonds are the mostly the same set of keys used for stocks.  We still solve for price (buy), selling price (sell), and yield. 

**  Annual yield mode is automatic

**  payments during investments are now coupons, which the coupon rate is entered with the [ CPN ] key

**  commissions, capital gains tax rate, and income tax rate are still included

I do believe that bonds make it into later calculators, such as the TI BA II Plus.   

Options (Security Type is "Blank")

Generally the same concept, solve for price (buy), selling price (sell), and yield; with variables including commissions, capital gains tax, and income tax.   What is different is the use of call and put prices.  

I realize that this is a short introduction, as I plan to learn more about the features of the Investment Analyst.  

Keyboard

The keys are little hard, careful pressing of them are required. I find this to be the case of TI's calculators from the late 1970s/early 1980s. Thankfully the keyboard is still workable.  

I wonder if the keyboards were lot better, calculators outside of the "mainstream" such as the Investment Analyst and the TI-54 (which I reviewed in 2018) would have been given another edition.  

Closing Thoughts

This is a curious calculator that fit a specialized niche: stocks, bonds, and options.   Not too many calculators go into this area, I believe Calculated Industries had one dedicated to Wall Street calculations.  I have a feeling I am going to learn a lot about investments from going through the well detailed manual.  

This is definitely a collector's item.  

Source:

"Texas Instruments Investment Analyst"  Datamath Calculator Museum.  December 5, 2001.  Last retrieved March 4, 2022.    http://www.datamath.org/Sci/Slimline/Investment-Analyst.htm   

Until next time,

Eddie

All original content copyright, © 2011-2022.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Retro Review: Casio FC-1000 Financial Consultant

Retro Review:   Casio FC-1000 Financial Consultant

Birthday post!

Quick Facts:

Model:  FC-1000 Financial Consultant

Company:  Casio

Years:  1988-early 1990s

Type:  Finance and Graphic

Batteries:  3 x CR-2025

Memory: 2,470 programming steps

Contrast wheel 

Like the Casio fx-7500G, the FC-1000 is a foldable calculator which is very small and light.  

Features

The main modes of the FC-1000 are come in two categories:  system modes and calculation modes.

System Modes

Run Mode (Mode 1):  This mode is for calculations and running programs.

Write Mode (Mode 2):  This mode is for writing programs, in one of 10 slots, Prog 0 to Prog 9.

Program Clear Mode (Mode 3):  Erase programs in this mode.  Clear all programs by pressing [ SHIFT ] [ DEL ] ( Mcl ).

Calculation Modes

Financial Mode (Mode 4):  This mode is for financial calculations including time value of money (simple/compound/monthly C.I.), amortization, D.C.F. (discounted cash flows including NPV, IRR, NFV), bonds, depreciation, and cost/sell/margin.  The financial calculations are accessed by pressing the [ MENU ] key.   One of the great things of the FC-1000 is that it has a big screen to list variables and menu choices.  

Linear Regression Mode (Mode 5):  This mode fits bivariate data to the equation y = a + bx.  

SD Mode (Mode 6):  Single variable statistics

Mathematical Functions

The FC-1000 has a set of mathematical functions tailored to financial calculations:

*  powers and roots

*  logarithms

*  integer and fraction parts

*  factorials of positive integers

*  days between dates

How to figure out how to calculate days between dates:  

month_before [ DATE ] day_before [ DATE ] year_before [ DATE ] [ - ]

month_after [ DATE ] day_after [ DATE ] year_after [ DATE ]

If a two digit year is entered, it is implied that the year is 19##.  Thankfully four digits years are allowed, so this calculator can be used in the 21st century.   (Trivia:  I will be alive 16,436 days today using the 365 day mode).

The date separate is indicated by a forward slash.  

Programming 

The FC-1000 uses the Casio basic programming language.  The following commands available are:

Comparisons and the jump command:

[ test ] ⇒ [ do if true ] : or ◢  [ skip to here if false ]

Goto and label commands (Lbl 0-9)

Count jumps Isz (increment and skip on zero) and Dsz (decrement and skip on zero)

We can also store values in financial variables that are accessed through the menu system.  

As mentioned before, the space has a capacity of 2,470 steps over 10 program slots. 

Graphing

The FC-1000 has graphing, but is limited to certain financial applications:  bonds, amortization, and depreciation.   Depending on what type of graph, pressing [ Trace ] will highlight the next period, and [ Shift ] [ Trace ] will rotate between different points of data.

For instance, in bonds, the [ Shift ] [ Trace ] combination rotates between price (PRC), coupon (CPN), and redemption value (RDV).

In amortization, the cycle is interest (INT), principal (PRN), and the nth payment (n).

In depreciation, the cycle is the year's depreciation (Depr) and year (n).  

Closing Thoughts

I love the form factor of the FC-1000 and how compact the calculator is.   However, the calculator is light weight and extra care is a must.  I wish the graphing module allowed us to graph functions and added statistical graphs.   

The FC-1000 can be difficult to collect, hence prices may be higher than a lot of vintage calculators.  

Until next time,

Eddie

All original content copyright, © 2011-2022.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Review and Instruction: Senario FC-500 Financial Calculator

Review and Instruction: Senario FC-500 Financial Calculator

Announcement:  Twelve Days of Integrals

In spirit of the Twelve Days of Christmas, I present the Twelve Days of Integrals:  starting December 25, 2021 to January 5, 2022.  I hope everyone has a happy, health, and sane holiday season!

Now on to the review.

Review: Senario FC-500 Financial Calculator

Quick Facts

Model: FC-500

Company: Senario

Years: ??, sometime in the 2010s?

Memory Register:  1 user memory with separate registers

Battery:  Battery, 2 x LR44

Screen:  12 digits

Logic:  Chain

I purchased the Senario FC-500 on eBay for relatively cheap.  The one I purchased did not come with an instruction manual, and I couldn't find one online.   

Through playing with the calculator and research with other financial calculators, the FC-500 models itself after the Hewlett Packard HP 12C.  

What makes this financial calculator a little unique is the wonderful presence of 40 U.S.-metric conversions.   The FC-500 is a feature rich financial calculator.  

I have yet to find instruction on how to change the number of decimal points displayed, if that is even available.  Most financial calculators default to the 2 decimal point setting, and that would be the expected setting.  This would be one of my sticky points for the FC-500, the other would be lack of user memory registers.  

The cash flow convention is followed:  positive for cash inflows (deposits and receipts), negative for cash outflows (payments).  The key with a magnifying glass over a document, which is located on the second row, sixth key (right-most key) is the compute/calculate key.  On this blog I will designate this key as the [(search)] button.

Features

*  Time Value of Money

*  Depreciation (Straight Line, Sum of the Years Digit, Declining Balance)

*  Sell/Cost/Margin (SEL, CST, MGN)

*  Interest Conversion:   Effective vs Nominal (APR)

*  Percent Calculations (%, percent change, % of total)

*  Currency conversions

*  Tax calculation (TAX+ and TAX-) 

*  Days between dates and date calculations (four digit years)

*  Statistics including Linear Regression

The rest will be an instruction sheet for those who are looking for a manual.  For anything I missed, you may want to look at the HP 10BII+ or HP 12C manual and it may fill the rest of the gaps.   Hope this helps.

Operating the FC-500

Time Value of Money (TVM)

PV:  present value

n:  number of payments, ×12

i:  periodic interest rate, ÷12

PMT:  payment

FV:  future value

Magnifying glass, designated as [(search)]:   Solve/CPT

B/E:  Beginning/End Toggle

Cash flow convention is followed

Example:

PV:  0.00

n:  3 years 

i:  3.86% compounded monthly

payment:  $50.00 per month

0 [ PV ]

3 [SHIFT] (×12)

3.86 [SHIFT] (÷12)

50 [+/-] [ PMT ]

[(glass)] [ FV ] returns 1,905.11893693

Amortization Procedure

1.  Enter n, i, PV, and any balloon amount in FV.

2.  Compute PMT.

3.  Enter period 1 to n, second period, press [SHIFT] (AMORT)

4.  Accumulated Interest,  [ X←→Y ], Accumulated Principal

5.  [ RCL ] [ PV ]: remaining balance

6.  [ RCL ] [ n ]: number of payments amortized

7.  To do the next batch, press [ SHIFT ] (AMORT), repeat steps 4 through 6

Example:

Loan:  $189,000.00

I/YR:  4.8% compounded monthly

Years: 20 years of monthly payments

No balloon payment

Amortize the first 2 years of 12 month payments

189000 [ PV ]

20 [SHIFT] [ ×12 ]

4.8 [SHIFT] [ ÷12 ]

0 [ FV ]

[(search)] [ PMT ] returns -1,226.529641804

First 12 Payments

0 [ n ] 12 [SHIFT] (AMORT)

Accumulated Interest:  -8,946.10891465

Accumulated Principal: [ X←→Y ], -5,772.24650183

Balance:  [ RCL ] [ PV ],  183,227.753498

Second 12 Payments

12 [SHIFT] (AMORT)

Accumulated Interest:  -8,662.86358088

Accumulated Principal: [ X←→Y ], -6,055.4918356

Balance:  [ RCL ] [ PV ],  177,172.261662

EFF/NOM conversion

Convert from NOM (APR) to EFF

payments per year [ n ]

nominal rate [ NOM ] 

[(search)] [ EFF ] 

Example:  NOM = 6%, payments per year = 24

24 [ n ]  6 [ NOM ]  [(search)] [ EFF ] returns 6.17570442629

Convert from EFF to NOM (APR)

payments per year [ n ]

nominal rate [ EFF ] 

[(search)] [ NOM ] 

Example:  NOM = 6%, payments per year = 24

24 [ n ]  6 [ EFF ]  [(search)] [ NOM ] returns 5.83397001049

Percent Change

old [ X←→Y ] new [ Δ% ]

Example:   4750 [ X←→Y ] 4200 [ Δ% ] returns -11.5789473684

Days Between Dates

first date [ X←→Y ] second date [SHIFT] (ΔDAYS)

Example:  3.141977 [ X←→Y ] 12.092021 [SHIFT] (ΔDAYS) returns 16,341

(M.DY year mode)

(March 14, 1977  to December 9, 2021)

Percent Total

whole [ X←→Y ] part [ %T ]

Example:  85 [ X←→Y ] 41 [ %T ] returns 48.2352941176

Date Addition

date [ X←→Y ] number of days [SHIFT] (DATE)

Day number:  1:  Monday to 7: Sunday

Example:  Determine the date 90 days from November 15, 2021?  (M.DY year mode)

11.152021 [ X←→Y ] 90 [SHIFT] (DATE) returns 2.132022-7

(Sunday February 13, 2022)

Tax Addition and Subtraction (Sales Tax)

To set the tax rate:  rate [SHIFT] (RATE SET)

To add the tax rate:  [TAX+]:   x∙(1+rate/100)

To subtract the tax rate:  [TAX-]:  x/(1+rate/100)

Example:  Set rate at 9.5%

200 [TAX+] returns 219

150 [TAX-] returns 136.986301369

Unit Conversions 

40 conversions

Use the blue keys:

[ ← ]:  metric to US

[ → ]: US to metric

Statistics - Linear Regression

Date:  x [ X←→Y ] y [ Σ+ ]

Registers used:   (not used for other purposes)

[ RCL ] [ 1 ]: N

[ RCL ] [ 2 ]: Σx

[ RCL ] [ 3 ]: Σx^2

[ RCL ] [ 4 ]: Σy

[ RCL ] [ 5 ]: Σy^2

[ RCL ] [ 6 ]: Σxy

Depreciation

[ n ]:  life of the asset in years

[ PV ]:  cost

[ FV ]:  salvage value, if any

[ i ]:  rate (for declining balance only)

year # [ SHIFT ] ( SL ):  Straight Line Depreciation  (press [ X ←→ Y] for book value)

year # [ SHIFT ] ( SOYD ):  Sum of the Year's Digits Depreciation  (press [ X ←→ Y] for book value)

year # [ SHIFT ] ( SL ):  Declining Balance Depreciation  (press [ X ←→ Y] for book value)

Simple Interest

n:  number of days

i:  annual interest rate

PV:  principal amount

Enter 0 in PMT and FV

Press [SHIFT] (INT) for simple interest

Example:

Calculate the simple interest of a 30-day loan of $1,400.00.  The annual rate is 6.5%.

1400 [ PV ]

30 [ n ]

6.5 [ i ] 

0 [ PMT ], 0 [ FV ]

[SHIFT] (INT) returns -7.583333333333  (360-day year)

[ X ←→ Y] -7.7945205479 (365-day year)

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Retro Review: Texas Instruments Personal Banker

Retro Review:   Texas Instruments Personal Banker

Quick Facts:

Models:  Personal Banker

Company:  Texas Instruments

Years:  1987 - 1988

Memory Register:  1 independent memory, 5 financial registers

Battery:  Solar

Finance in a Clamshell Calculator

The Texas Instruments Personal Banker is a basic solar financial calculator.   The calculator opens up like a book.  The gray case gives the calculator a professional look.

On the left side, we have the arithmetic functions with the memory functions (M+, M-, MRC).   There are three keys of note:

[ AC ]:  The key clears everything, resets the format to 2 decimal fixed mode, clear the memory register, and the financial register.  

[ CE/C ]:  Clear the last entry but keeps everything in the memory register and financial registers intact.

[ DEC ]:  This sets the fixed decimal format.  The default is 2 places.  [ DEC ] [ . ] (decimal point) sets the Personal Banker to floating mode.  

On the right side are the Time Value of Money keys:

[ 1st Amt ]:   Present Value  (PV)

[ # Pmts ]:  Number of Payments (n)

[ Int Rate ]:  Interest Rate per Period (i%)

[ Pmt Amt ]:  Payment (PMT)

[ Final ]:  Future Value (FV)

The [ Solve ] and [ Recall ] keys work exactly the way you expect.  

The cash flow convention (positive for inflows, negative for outflows) is followed.

It is very simple.  A four function calculator with a full time value of money solver.

To help the user, included with the Personal Banker are four cards:

Blue Car Symbol:  Loans & Mortgages

Red Dollar Symbol:  Savings with Periodic Deposits

Gold Stock Graph Symbol:  Investments

Green House Symbol:  Loans & Mortgage with a Balloon Payment

Keyboard

The feel of the keys are solid.  However, the keys take a small fraction of a second for the key to register, so make sure the key registers before typing the next key.  

Verdict

The Personal Banker is a basic financial calculator.  I really like the folding design on this calculator and how the keys work.  Unfortunately, the high price point of $50 (see source) and it's basic set of functions (arithmetic, percent, time value of money, but no cost-sell-margin solver, amortization, statistics, logarithms, or exponents) did not help sales of the Personal Banker.  

It is a good collector item, since vintage solar-powered Texas Instruments financial calculators yield premium prices.

Source

Woerner, Joerg.  "Texas Instruments TI-2600 Personal Banker"  Datamath.  Updated July 22, 2002.  Retrieved January 23, 2021.  http://www.datamath.org/Sci/Modern/PersonalBanker.htm

On Sunday, we'll take another trip back in time.  

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Financial Calculators: Deferred Mortgages: Solving for Payment and Price

Financial Calculators:  Deferred Mortgages: Solving for Payment and Price

Finance Now, Pay Later!

When a customer financing a loan or mortgage, and the customer can enjoy the benefits for a period of months prior to being required to make the first payment, we are dealing with a deferred mortgage.   Interest is accrued from the beginning of the mortgage.

The procedures outlined on this blog entry can be applied to any financial calculator* with time value of money keys, such as the HP 12C and the HP 10bII+ (see source below).  

* The procedure should be fine for most financial calculators.   Check your manual for details.  

Deferred Mortgage:  Finding The Monthly Payment

Part 1:

Set the calculator to END mode.

N:  Enter the number of deferred payments minus 1

I:   Enter the interest rate of the loan

PV:  Enter the borrowed amount as a negative number

PMT:  Set to 0

Solve for FV

Part 2:

PV = FV from part 1   ( RCL FV, STO PV )

N:  Enter the number of payments of the term

I = interest rate of the loan

FV:  Enter the balloon payment as a negative number.  If there is no balloon payment, enter 0.

Solve for PMT, this is your payment of the deferred mortgage.  

Example 1:  

A homeowner finances a house for $455,000.00.   The mortgage lasts for 30 years at 2.86%.   No payment is due for the first six months of the mortgage.  

Part 1:

N: 6 -1 = 5

I:  2.86% annual rate, about 0.24% per month

PV:  -455000.00

PMT:  0.00

FV = 460447.99

Part 2:

PV:  460447.99

N:  30* 12 = 360

I:  2.86% annual rate, about 0.24% per month

FV:  0.00

PMT = -1906.67

The monthly payment is $1,906.67.

Example 2:

A homeowner purchases a fixer-up property for $149,000.00.  The buyer secures a 15-year mortgage at 4%.  The end of the loan requires a $1,000.00 balloon payment but allows the buyer to defer the first payment for five months.

Part 1:

N:  5 - 1 = 4

I:  4% annual rate, about 0.33% per month

PV:  -149000.00

PMT: 0.00

FV = 150996.62

Part 2:

PV:  150996.62

N:  15 * 12 = 180

I:  4% annual rate, about 0.33% per month

FV: -1000.00

PMT = -1112.84

Deferred Payment:  Calculating the Price of the Mortgage

Part 1:

Set the calculator to END mode.

N:  Enter the number of payments of the term

I:   Enter the interest rate of the loan

PMT: Enter the payment as a positive number

FV: Enter the balloon payment as a positive number.  If there is no balloon payment, enter 0.   

Solve for FV

Part 2:

FV = PV from part 1   ( RCL PV, STO FV )

N:  Enter the number of deferred payments minus 1

I = interest rate of the loan

Set PMT to 0

Solve for PV, this is your price of the deferred mortgage.  

Example 3:

An owner enters a lease which requires at monthly payment of $495.00.  The lease lasts for 8 years at 6.69%.  There is no balloon payment at the end of the lease.  The lease allowed the owner to defer the first required payments for three months.  What is the value of the lease?

Part 1:

N:  8 * 12 = 96

I:  6.69% annual rate, about 0.56% per month

PMT:  495.00

FV:  0.00

PV = -36721.17

Part 2:

FV:  -36721.17

N:  3 - 1 = 2

I:  6.69% annual rate, about 0.56% per month

Set PMT to 0

PV = 36315.13

The value of the lease is $36,315.13.

Example 4:

An owner executes a 30-year, 3% mortgage with the required payment of $1,005.85.  The mortgage allows for the first payment to be deferred for six months.  A $1,000.00 balloon payment is required.  What is the price of the mortgage?

Part 1:

N:  30 * 12 = 360

I:  3% annual rate, 0.25% per month

PMT:  1005.85

FV:  1000.00

PV = -238983.97

Part 2:

FV:  -238983.97

N:  6 - 1 = 5

I:  3% annual rate, 0.25% per month

Set PMT to 0

PV = 236018.94

The value of the lease is $236,018.94.

And that is how we work with deferred mortgages.  

Source:

Greynolds Jr., Elbert B. and Aronofsky, Julius S.  Practical Real Estate Financial Analysis: Using The HP 12C Calculator:  A Step-by-Step Approach   Real Estate Education Company: Dearborn Financial Publishing, Inc.  1983.  ISBN 0-88462-378-5

Eddie

All original content copyright, © 2011-2020.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Retro Review: Casio FC-100 Financial Calculator

Retro Review:  Casio FC-100 Financial Calculator

Quick Facts:

Model:  FC-100
Company:  Casio
Type:  Finance
Years:  1987 - 1991
Display:  10 digits
Batteries:  1 CR 2035

I paid $18 on eBay, I suspect that the original price was somewhere in the $20 - $30 neighborhood. 

All the Basics Are Covered

Time Value of Money

The FC-100 has the following financial features:

Time Value of Money:  The standard cash convention is used, where cash inflows are positive, cash outflows are negative.  The [COMP] key is used to compute the needed variable.  There are two keys dedicated to amortization.  Given the number of payments:

[AMRT]:  principal paid on the nth payment, interest paid on the nth payment, balance after the first n payments

[ACC]:  accumulated principal on the first n payments, accumulated interest on the first n payments

Similar to the Hewlett Packard HP 12C, the 12× multiplies the number of years by 12 and stores the result in n (number of payments), while the 12÷ divides the annual interest rate and stores the result in i% (periodic rate). 

Cash Flows

The FC-100 can store up to 16 cash flows.  The two calculations available are net present value and initial rate of return (NPV and IRR, respectively).  The interest rate is entered using the [ i% ] key.  We can clear all the cash flows quickly by KAC (pressing [SHIFT] [ Min ]). 

Days Between Dates

There are two modes that deal with date setting:  actual (365) and 30/360 year.  There are two functions:  days between dates and adding/subtracting dates.  Only days between dates is available on the 365 setting. 

What is cool about the FC-100, is the dates are allowed between January 1, 1900 and December 31, 2099. This is pretty impressive for a calculator of the late 1980s.  Dates in the 1900 century are entered with two-digit years while dates in the 2000 century are entered with four-digit years. 

The result of any calculation will include the day of the week (0 for Sunday, 6 through Saturday).

Statistics

Single variable and linear regression are available.  The FC-100 uses the six registers for statistical sums:

K1 = ⅀x^2
K2 = ⅀x
K3 = n
K4 = ⅀y^2
K5 = ⅀y
K6 = ⅀xy

Memory Registers

Another theme of Casio calculators from the 1980s are the use of independent memory registers K1 through K6.  Store data by using Kin, recall data by using Kout.  Storage arithmetic is also available.  An independent memory register M is available.

Keyboard

The FC-100 has an on-off switch on the side of the keyboard.  I like this placement.

The keyboard is clean, the keys are nice and responsive.  I like the size of the keys of the numeric and arithmetic keys (brown).  The keys on the top four rows (in ivory) are smaller in size, a little smaller than I like.  However, the keys are comfortable to press. 

Verdict

The Casio FC-100 is a great user-friendly financial calculator. 

Source:
"Casio FC-100 (FINANCIAL CONSULTANT)"  calculator.org  https://www.calculator.org/calculators/Casio_FC-100.html  Retrieved December 6, 2019

Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

What’s New: CALC 1 by CalcFxC, LLC

What’s New:  CALC 1 by CalcFxC, LLC

Programmer/Author:  CalcFxC, LLC

Platform:  iOS (iPhone, iPod Touch, iPad)

Price:  Up to $5.99 for the full, non-ad version

There is a free version, but it is with ads and you may not get all the features you want.  There are in-app purchases on the free version if you want. 

Apple App Store Link:  https://itunes.apple.com/us/app/ad-free-calc-1-financial-calculator/id1073629173?mt=8

Web Site:  http://www.calcfxcllc.com/

This blog entry will focus on some of the update (as of 3/24/2016). 

I reviewed the app on a previous blog entry:  http://edspi31415.blogspot.com/2012/10/review-of-freecalcfxc.html

To review, CALC 1 (previously named CalcFxC), has focused calculators and formula calculators.  Focused calculators are calculators that are set on a specific theme or task.  This includes the general, time value of money, statistics, conversions, and general (scientific) calculators.    Hold any key for a second, and you will see help text that applies to the key.  Formula calculators are calculators that are based on equation solving.  This includes solving percentage problems, profit margin, effective interest rate vs nominal interest rate, permutations, combinations, probability density functions, and polynomial solvers.  You can also make a customized focused or formula calculator. 

We also have Form Calculators.  These are guided calculators that answer specific questions, such as finding the monthly payment of a loan, a time value of money worksheet, an amortization worksheet (which can be copied and emailed), depreciation, and dates. 

Some of the New Features

Value Preview

This is my favorite of the new update (as of 3/24/2016) is the value preview.  Any storage register, be it the time value of money, formula register, or variables, you will see the current value of the register printed directly on the key. 

Swap Key (iPhone/iPod Touch) takes you to Currency Conversion

The swap key takes you the currency conversion and automatically takes the number on the X Stack (bottom stack) as its argument.  The best part is that the most current conversion rates are used (assuming your device is connected to the internet).  Once conversion is complete, the results are placed on the X stack.

Chain Mode

New to CALC 1 is chain mode.  Most four-function, non-scientific calculators that you find operate on Chain Mode.   Operations in chain mode work on the number in the display (x-stack) in the order you press the key, ignoring the Order of Operations.  For example:

Pressing 7 [ + ] 2 [ x ] 5 [ = ] in chain mode returns 45.  (Under Order of Operations, the 7+2*5 = 17)

CALC 1 also has Algebraic and RPN entry modes. 

Form Calculator Results are placed in History

This not only transfers single amounts but also any applicable tables.  To see the details of any Form Calculator related history item, click on the information button (the blue I in a circle).  This is useful if you want to work with a lot of what-if scenarios or if you making a set of calculations that you want to refer to at a later time. 

Please check this app out, Roger Carey has a done a solid job on this calculator. 

This blog is property of Edward Shore, 2016.