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Scientific Calculator — Free Online Tool
Solve everything from basic arithmetic to trigonometry, logarithms and powers — instantly, with a clean keypad and full keyboard support.
Instant results — no waiting
No sign-up needed
Free forever
How it works
1Tap the keys (or type on your keyboard) to build your expression.
2Press = to evaluate — trig runs in Degrees or Radians, your choice.
3Keep calculating — the result becomes the start of your next expression.
Frequently asked questions
Why does sin(30) give 0.5? Is that degrees or radians?
The calculator defaults to Degrees mode (DEG), like a school calculator — so sin(30) = 0.5. Switch to RAD mode above the keypad if you need radian angles.
Is my calculation data sent anywhere?
No. Everything is computed locally in your browser with the math.js library — no servers, no sign-up, no tracking of your expressions.
What does "Error" mean?
It means the expression couldn't be evaluated — for example an unmatched parenthesis, a missing operand like "5 +", or a mathematically undefined result like 0/0. Press C and try again.
Trig · logarithms · powers · roots · percentages · parentheses — evaluated safely with math.js, no eval().