What this scientific calculator does
Everything a good school or desk scientific calculator does, on a screen big enough to read comfortably. The four arithmetic operations with full parentheses and the standard order of operations; powers and roots; the six trigonometry functions (sin, cos, tan and their inverses) in degrees or radians; natural and base-10 logarithms; factorials; percentages; the constants π and e. Type whole expressions — (3+4)×5², sin(30)+cos(60), log(1000) — and press = (or Enter) once, rather than chaining one operation at a time and losing track of where you were. The line above the display keeps your last expression visible after the answer appears, so you can check what you actually asked — the single most common calculator error is not arithmetic at all, but typing a different question than the one in your head. Implied multiplication works the way maths is written: 2π, 3(4+1) and (2+1)(3+1) need no × sign.
A note on how it works, because it matters for trust: your expression is evaluated by a small mathematical parser written for this page, which reads the expression the way a mathematician would — numbers, operators, functions, parentheses — and refuses anything it does not understand with a plain error message. It is never handed to a general script interpreter. That is the safe way to build a calculator, and it also makes the behavior predictable: invalid input like 5++ or sqrt( gets an explanation, not a silent wrong answer. Everything happens in your browser; nothing you calculate is transmitted or stored.
Degrees or radians?
The DEG/RAD button is the one control new users trip over, so here is the whole story in one paragraph. Angles can be measured in degrees (a full turn is 360, a right angle is 90) or in radians (a full turn is 2π ≈ 6.283, a right angle is π/2 ≈ 1.5708). School maths, navigation, construction and everyday life use degrees; university mathematics and physics mostly use radians. The calculator starts in DEG. In DEG mode, sin(90) = 1 exactly as you would expect; switch to RAD and sin(90) means the sine of 90 radians — a different, stranger number. Inverse functions follow the same mode: asin(1) returns 90 in DEG mode and 1.5708 in RAD mode. If a trigonometry answer ever looks absurd, check the mode first — it is the cause nine times out of ten.
Handy things to try
- Percentages: the % key divides the number before it by 100, so 250×8% gives the tax on 250 directly, and 80×20% gives 16 — the amount of a 20% tip on 80 — ready to add on.
- Powers and roots: xʸ is the ^ key: 2^10 = 1024. Roots are powers in disguise — cube root of 27 is 27^(1/3) = 3 — or use √ for square roots: sqrt(144) = 12.
- Factorials: 5! = 120, the number of ways to arrange five things. They grow ferociously — 20! already exceeds two quintillion — and only whole numbers zero and up are allowed.
- Any log base: log is base 10 and ln is base e. For another base, divide: log base 2 of 8 is log(8)/log(2) = 3.
Frequently asked questions
Can I use my keyboard with this calculator?
Yes. Type numbers and the operators + − * / ^ % ! and parentheses directly, press Enter (or =) for the result, Backspace to delete the last character and Escape to clear. Function names like sin, sqrt and log can be typed too — for example sin(30) or sqrt(144).
What is the difference between DEG and RAD mode?
Trigonometry functions can take angles in degrees (a right angle is 90) or radians (a right angle is π/2 ≈ 1.5708). This calculator starts in DEG mode because most school and everyday work uses degrees. Tap the DEG/RAD button to switch; the mode also applies in reverse — in RAD mode, inverse trig functions like asin return radians.
What do log and ln mean here?
Following the convention on physical scientific calculators, log is base 10 (log(1000) = 3) and ln is the natural logarithm, base e (ln(2.71828…) ≈ 1). There is no separate log-base-2 button; use the change-of-base rule, log(x) ÷ log(2).
Does this calculator follow the order of operations?
Yes — parentheses first, then powers, then multiplication and division, then addition and subtraction, exactly as in mathematics. It also understands implied multiplication, so 2π, 3(4+1) and (2+1)(3+1) all work without typing the × sign. Expressions are evaluated by a proper parser built into the page, never by handing your input to a script runner.
Private by design: calculations happen in your browser. Nothing you type is sent anywhere or remembered after you close the tab.