History

Math Constants

Archimedes' Constant Pi
3.1415926535Alt-P

Natural Logarithmic Base
2.7182818284Alt-E

Golden Ratio
1.6180339887Alt-G

Euler's Constant
0.5772156649Alt-Y

√2

Pythagoras' Constant
1.4142135623Alt-S

√3

Theodorus' Constant
1.7320508075Alt-T

√5

Golden Ratio's Friend
2.2360679774Alt-F

Speed of Light (m/s)
299792458Alt-C

Examples

Calculate	Button/Key Sequence
2 x 3	23=
(2 x 3) + 10	23+10=
2 x (3 + 10)	3+102=
√ 2	2
1/1024	1024
2 x √ 2	22=
-2³	2==
√ 3² + 4²	3+4=
π x 10²	10=Alt-P=
256 + 10%	256+10=
5% of 25	525=
5³ √ 2 + 6	2+6= 5===

Keyboard Shortcuts

Button	Key

0...9	0 ... 9	Digits

AC	Esc	All Clear
CE	Delete	Clear Entry
		Backspace
=	=orEnter	Equals
.	.	Decimal Point

	+	Add
	-	Subtract
	*orX	Multiply
	/	Divide

M+	A	Memory Add
MC	C	Memory Clear
MR	R	Memory Recall
M−	S	Memory Subtract

	I	Invert +/-

	F1	Square Root
	F2	Percent
	F3	Reciprocal 1/x
	F4	Squared x²

	Alt-P	π - Pi
	Alt-E	e - Natural Log
	Alt-G	ϕ - Golden Ratio
	Alt-Y	γ - Euler's Constant
	Alt-S	√2 - Square Root 2
	Alt-T	√3 - Square Root 3
	Alt-F	√5 - Square Root 5
	Alt-C	c - Light (m/s)

Reset

Settings

Display

Floating Point

Digit Grouping

Decimal Symbol

0.0

Negative Number

0.0

Rounding

Round calculated Fixed Point results
when they are displayed.

Fix Math Errors

Turns 1.3499999999... into 1.35
From accuracy limit of 64-bit values.

Show Math

Displays math expression while it is
entered:e.g. 20 + 5 × 5 − 15

Save Work

Loads history, memory, and settings
when calculator is restarted.

To Calculator

Bookmark this link for above settings . . .

Features

12-Digit display, 16-Digit math accuracy
Simple left to right math calculations
Fixed or floating point operation
4 Math operands (Add, Subtract, Multiply, Divide)
5 Math functions (Square Root, Squared, Reciprocal, Inverse, Percent)
4 Memory functions (Add, Subtract, Recall, Clear)
Clear all, clear entry, and backspace
Digit grouping 000's along with
international ',' and '.' use settings
Keyboard input with button feedback
Reusable math calculation history
(last 100 calculations)
Savable settings, history, memory, and display
Easy to repeat last operation
Displays math expression
Copy and paste values
Clear error messages
Resizable

About

Brand:Internet Calculator

Name:Big Red Calculator

Version:

Calculator excels in . . .

Accuracy
Robustness
Ease of Use
Speed

Perfect for use in meetings, classrooms,
and at home.

Big Red Calculator

A free online calculator with a bold red design, 12-digit display, calculation history, and memory functions. Resize it to any window size — it fills your screen whether you're on a desktop or laptop.

The Big Red Calculator saves your work by default, so when you reopen it you can continue right where you left off — even in the middle of a calculation. It supports full keyboard input, a repeating equals key, and stores your last 100 calculations for fast one-click reuse.

For everyday use at home, in the office, or in the classroom. No download, no installation, and no account required. Just open it and start calculating.

12-Digit Display — with 16-digit math precision
Calculation History — stores last 100 calculations for fast reuse
Memory Functions — store, recall, add to, and subtract from
Resizable — expands to fit any desktop or laptop window
Automatic Save — continues where you left off after closing
Keyboard Support — full keyboard input with visual key feedback
International Formats — choose digit grouping and decimal symbol
Nothing to Install — works in any modern web browser

Frequently Asked Questions