Spotlight: Casio fx-451 Calculator
Quick Facts
Model: fx-451
Company: Casio
Type: Solar Scientific Algebraic
Memory: 1 (store, recall, exchange (X←→M), sum (M+), subtract (M-))
Years in Production: 1985 to 1987 per calculator.org (https://www.calculator.org/calculators/Casio_fx-451.html)
Display: 10 digits
Casio Ledudu’s page on the fx-451: https://casio.ledudu.com/pockets.asp?lg=eng&type=1016
Folding Calculator Power
The Casio fx-451 is a folding scientific calculator. On the left side, there are the arithmetic keys, the shift, mode, and on keys, the display (10 digits), and the solar panel that operates the calculator. The right side has touch, rubber-like, membrane keys. The right side has all the scientific, statistical, fraction, base conversion, and imperial/metric conversions.
You can see my review of the fx-450 from 2018 here: https://edspi31415.blogspot.com/2018/07/retro-review-casio-fx-450-calculator.html
The available modes for the fx-451 are:
. (decimal point): SD (Standard Deviation), single variable statistics. Statistics functions are marked in blue.
0: DEC. Decimal mode. This is also the calculator’s normal/computation mode.
1: BIN. Binary integer mode (base 2). Boolean logic operators are available and are marked in green.
2: OCT. Octal integer mode (base 8). Boolean logic operators are available and are marked in green.
3: HEX. Hexadecimal integer mode (base 16). Boolean logic operators and the letter digits A-F (A=10 to F=15), are available and are marked in green.
4: DEG. Degree angle mode.
5: RAD: Radians angle mode.
6: GRA: Gradians angle mode.
7: FIX: Fixed point decimal setting
8: SCI: Scientific notion decimal setting.
9: NORM: Floating point decimal setting. Numbers less than 0.01 are shown in scientific notation form.
The engineering keys, [ENG] and [←ENG], temporarily show the number in display using scientific notation where the exponents are in multiples of 3 (i.e. 10^-6, 10^-3, 10^0, 10^3, 10^6, etc.)
Like many Casio scientific calculators, the fx-451 sports the fraction key [a b/c], allowing both entry of fractions (proper and mixed), and conversions between fractions and decimal approximations.
In addition, the fx-451 has nine scientific constants. (by pressing [SHIFT] [1-9]). The constants are:
1. Speed of Light (c)
2. Plank’s constant (h)
3. Universal gravitational constant (G)
4. Electron charge (e)
5. Mass of an electron (me)
6. Atomic mass constant (u)
7. Avogadro’s constant (Na)
8. Boltzmann constant (k)
9. Molar volume of ideal gas (Vm)
All units are in SI units, and are listed with the constant on the keyboard.
The fx-451 Adds Imperial/Metric Conversions
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The fx-451 is a later version of the fx-450 and has added a set of eight imperial/metric conversions:
Temperature: degrees Fahrenheit/Celsius
Length: inches/millimeters
Volume: gallons/liters, ounces/grams
Mass: pounds/kilograms
Energy: calories/Joules
Pressure: inches of Mercury/kilopascals, atm/megapascals
Conversions are called
by the two arrow keys [ ← ] and [ → ], and are they are marked in
gold. I always find conversions to be a welcome addition to any
calculator.
Solar Power
Like it’s cousin, the fx-450, the fx-451 operates only by solar and light power, hence no other batteries are required.
This is a fun calculator to have, and Casio does a really good job of including lots of features even in its basic scientific calculators.
Eddie
All original content copyright, © 2011-2026. 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.
