About this tool
This free online calculator handles the everyday arithmetic — add, subtract, multiply, divide, percentages, and sign changes — and you can drive all of it from the keyboard instead of hunting for buttons with the mouse. Nothing is uploaded: every calculation runs locally in your browser, and the history is kept in the page only, so it disappears when you close the tab.
Keyboard shortcuts
0–9— enter digits..— decimal point.-
+-*/— the four operators;xalso multiplies. -
Enteror=— calculate. Pressing it again repeats the last operation. -
Backspace— delete the last digit. -
Escorc— clear everything. %— percent.n— flip the sign (±).
How to use
- Display — the small line above shows the calculation in progress; the large line is the current number.
-
Percent — after
+or-it takes a percentage of the first number, so200 + 10 %gives 220. Otherwise it simply divides by 100. - History — every result is listed on the right; click one to bring that number back into the display.
- Theme — the toggle in the header switches between light and dark, and the choice is remembered on this device.
FAQ
Are my calculations sent to a server? No. Everything is computed in your browser and nothing leaves your machine.
Why does a long result get rounded? Results are
rounded to 12 significant digits. Computers store decimals in binary,
so without that rounding 0.1 + 0.2 would show as
0.30000000000000004 instead of 0.3.
Is there a scientific mode? Not here — this is a plain four-function calculator, kept small and fast on purpose.