Basic Free Online Calculator Service

Type a number, pick an operation (+, −, ×, ÷), type another number, then hit the equals button or press Enter. That's it. The AC button clears everything back to zero. The +/− button flips the sign of the current number, and the % button converts it to a percentage (handy for mental math shortcuts).

Keyboard shortcuts work too — just press the number keys, then +, -, *, or / on your keyboard. Press Enter or = to get the result. Escape clears the display. Most people find this faster than clicking buttons once they get used to it.

Splitting a restaurant bill. Figuring out how much you owe on utilities. Checking if a discount price actually makes sense. Doing a quick sanity check on a spreadsheet. These are the everyday situations where pulling out a dedicated calculator — even online — is faster than hunting through your phone for the built-in app.

It's also useful when you're already in a browser tab and don't want to switch windows. Just open this, do your calculation, and keep going. No installation, no sign-in, nothing to configure.

This is a basic arithmetic calculator, not a scientific one, so it processes operations in the order you enter them — left to right. If you type 2 + 3 × 4, it calculates (2 + 3) × 4 = 20, not the mathematically "correct" 2 + 12 = 14. If you need proper operator precedence, you'd want a scientific calculator. For simple day-to-day arithmetic, the left-to-right approach matches how most people think anyway.

• Can I use decimals? Yes. Just press the decimal point button (or the period key on your keyboard) between the integer and fractional parts.
• What's the largest number it handles? Anything JavaScript can represent as a floating-point number — well into the trillions. You won't hit a limit doing household math.
• Does it save my calculations? No. When you close or refresh the page, everything resets. For a running record, you'd need a spreadsheet or a dedicated app.
• Is it accurate for money? For most purposes, yes. Very large financial calculations can occasionally run into floating-point rounding (a quirk of how computers store decimals), so for anything critical, double-check with proper accounting software.