Calculator tools
Web Calculator
A four-function calculator with parentheses, percentages, memory keys, a running history and full keyboard support.
Runs locally in your browser
History (up to 30)
Press equals to record a calculation here; click a row to put its result back into the expression.
Evaluation is a hand-written tokeniser, shunting-yard pass and RPN walk — no eval and no dependency. Percent follows physical-calculator semantics: inside + and − it means “that share of the left operand” (100+10% = 110), while inside × and ÷ it is a plain value (100×10% = 10). Results are rounded to 12 significant digits before display, so 0.1+0.2 honestly reads 0.3. The keyboard works directly: digits, operators, brackets, percent, Enter to evaluate, Backspace to delete, Esc to clear.