Scientific Calculator

The Scientific Calculator extends everyday arithmetic with the functions a basic calculator leaves out — trigonometry (sin, cos, tan and their inverses), logarithms (base-10 and natural log), square roots, exponents, factorials and the constants π and e. It's built for students working through trigonometry or calculus homework, engineers double-checking a quick formula, and anyone who needs more than +, −, × and ÷ but doesn't want to dig out a graphing calculator app or open a spreadsheet. Like every tool on this site, it runs entirely in your browser — no install, no signup, and results appear as you type.

Type an expression the same way you'd write it on paper: `sin(30)`, `sqrt(16) + pi`, `log(1000)`, or `5!` for factorial. A degrees/radians toggle switches how trig functions interpret their input and output, since sin(30°) and sin(30 rad) are very different numbers — a common source of wrong answers on calculators that don't make the mode obvious. The button grid below the expression field inserts function names and constants for you if you'd rather click than type long function names.

The evaluator is a hand-written recursive-descent parser — the same category of technique used inside real calculator engines and programming-language interpreters — so it respects standard operator precedence and parentheses nesting, evaluates `2^3^2` right-to-left as `2^(3^2) = 512` the way mathematical convention dictates, and rejects malformed input with a specific error message (missing parenthesis, unknown function name, factorial of a non-integer) instead of silently producing garbage. No `eval()` or `Function()` is used anywhere, so there's no code-injection risk from what you type.

Because everything happens client-side, the calculator keeps working offline once the page has loaded and never transmits what you calculate. It's free with no usage limits, works identically on phones, tablets and desktops, and is fast enough to recompute on every keystroke without any noticeable lag.