Online scientific calculator

Type the expression with the buttons and see the result in real time; press = to lock it. It respects the order of operations and parentheses.

• √, x^y: square root and power.
• sin, cos, tan: trig functions — toggle DEG / RAD with the button.
• log (base 10), ln (base e), π and e.
• %: turns a value into its fraction (e.g. 50% = 0.5).

The DEG / RAD trap

The most common error on any scientific calculator is computing a trigonometric function in the wrong angle mode. sin(30) returns 0.5 in degrees and −0.988 in radians — two plausible results, and nothing in the answer signals which mode produced it. School trigonometry works in degrees; calculus and physics work in radians. Check the mode indicator before trusting a sine, cosine or tangent.

Order of operations

The calculator follows standard precedence: parentheses, then exponents, then multiplication and division, then addition and subtraction. That means 2 + 3 × 4 is 14, not 20. When in doubt, add parentheses — they cost nothing and remove every ambiguity, including the classic one around implicit multiplication.

Rounding and floating point

Results are computed in binary floating point, the same arithmetic every computer uses. That is why 0.1 + 0.2 can display as 0.30000000000000004: one tenth is a repeating fraction in base 2, exactly as one third is in base 10. For multi-step work, keep full precision and round only at the final answer.