Calculator
Click buttons or use your keyboard.
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Calculate fast with the Basic Calculator. Click the buttons or type: it handles order of operations, percent and sign change.
Click buttons or use your keyboard.
Expressions are evaluated with a small recursive-descent parser, so 2+3x4 correctly gives 14, not 20. No eval() is used: input is tokenized into numbers and operators first, which keeps the calculator safe from code injection.
Every button has a keyboard equivalent: digits, + - * / % ( ), Enter for equals, Backspace to delete and Escape to clear. The +/- key wraps the current number in a negation, and % converts it to a hundredth.