About
A calculator you can check. Every result stays on the tape next to the keypad, so when a number looks wrong you can see which step produced it instead of starting over.
Most on-screen calculators throw away the previous line the moment you press equals. That is fine until the total disagrees with the one on paper and you have no idea where the two of you parted ways. This one keeps a running tape, the way a desk adding machine does, and prints negative results in red so a sign error is visible at a glance. Tap any line on the tape to drop that number back into the expression.
What it can work out
Type a whole expression rather than one operation at a time. Brackets, powers and the usual order of operations all apply, and a number placed directly against a bracket multiplies, so 3(4+2) reads as 18.
- Arithmetic with
+,-,*,/,^and brackets - Percentages with a trailing
%, and factorials with a trailing! - Trigonometry in degrees or radians, plus the inverse functions
- Roots and logarithms:
sqrt,cbrt,ln,log,exp - The constants
piande, andansfor your last result
Keyboard
The keypad is there when you want it, but the whole thing is typeable. Digits and operators go straight in, Enter works out the answer, Backspace removes the last entry, and Escape clears the line.
Where it runs
The page carries its own arithmetic, so it works with no network once loaded. Switching the keypad to scientific, choosing degrees or radians, and the tape itself are remembered in your browser between visits. Nothing is calculated on a server.