Basic Calculator
A simple, fast online calculator. Tap the keys or use your keyboard. Handles percentages the way you'd expect, and keeps a history of your answers.
Keyboard: 0–9 + − * / % Enter Backspace Esc clears
How it works
How does the percent key work?
It works like a store calculator. 200 + 10% gives 220 (200 plus 10% of 200), and 200 − 10% gives 180. That's handy for tax and discounts. 50 × 10% gives 5, and 10% on its own is 0.1.
Does it follow order of operations?
Yes. Multiplication and division happen before addition and subtraction, so 2 + 3 × 4 = 14. The whole expression shows above the answer so you can check what you entered.
What do MC, MR, M+, and M− do?
They're memory keys. M+ adds the current answer to memory, M− subtracts it, MR puts the stored number into your calculation, and MC clears memory. An "M" appears on the display while memory holds a value.
Why does 0.1 + 0.2 show 0.3 here?
Computers store decimals in binary, which causes tiny rounding errors (some calculators show 0.30000000000000004). This calculator rounds results to 12 significant digits so you always see the clean answer.
Need more functions?
Try the scientific calculator for powers, roots, trig, and logs, or the RPN calculator if you prefer stack-style entry.