How to use
Click a key or type with your keyboard. Digits 0-9, operators + - × ÷, decimal . and percent % are supported. Press Enter or = to evaluate; Backspace deletes the last character; Esc clears everything.
±toggles the sign of the last number%divides the last number by 100- Your history is saved locally in your browser (up to 12 entries) and never uploaded
Formula & theory
The standard calculator follows classic operator precedence: parentheses → multiplication/division → addition/subtraction (PEMDAS / BODMAS), evaluated left-to-right.
How percentages are handled
A percent sign is expanded to "divide by 100": x% becomes x / 100. So 250 × 15% becomes 250 × 15 / 100 = 37.5.
A note on floating-point precision
JavaScript uses IEEE 754 double-precision floats, so some decimals have rounding noise (e.g. 0.1 + 0.2 = 0.30000000000000004). This calculator rounds the final result to 10 decimals to clean that up.