Scientific Calculator

How to use the scientific calculator

1. Type an expression, or build it with the keys.
2. Watch the running result, and read the message if it is not yet valid.
3. Press Enter to keep it in the history, and click any past result to reuse it.

About this tool

A scientific calculator earns the name by handling what a four-function one cannot: powers, roots, logarithms, trigonometry and factorials, in one expression. This one takes that expression whole rather than one keystroke at a time, which is the difference between checking your work and hoping. `2 * (3 + 4) ^ 2` is visible as written, so a misplaced bracket is something you can see rather than something you discover in the answer.

Operator precedence follows mathematical convention rather than left-to-right order. Powers bind tighter than multiplication and associate rightwards, so `2^3^2` is 512 and not 64. A leading minus binds looser than a power, so `-3^2` is −9 while `(-3)^2` is 9 — a distinction that spreadsheets famously get the other way round, and a genuine source of disagreement between tools.

The degrees and radians switch is the setting that silently produces wrong answers, so the current mode is stated beside the input rather than hidden in a corner. `sin(90)` is 1 in degrees and about 0.894 in radians, and both are correct answers to different questions.

Expressions are parsed rather than handed to the browser's own evaluator. Reaching for `eval` in a calculator means passing arbitrary text to the JavaScript engine on a page that can see everything else in the tab, and that is not a reasonable trade for saving a hundred lines. The input is tokenised and evaluated with the shunting-yard algorithm, which also means every error can say what is wrong and where.

Common uses

• Working through a calculation with brackets you can see and check.
• Trigonometry in degrees without converting by hand.
• Checking a result another calculator disagreed with.

Frequently asked questions

Is 2^3^2 equal to 64 or 512?

512. Exponentiation associates from the right, so it is 2 to the power of 3², not 2³ squared. This follows the mathematical convention.

Why is -3^2 negative?

Because the power binds tighter than the leading minus, so it reads as −(3²) = −9. Write (-3)^2 for 9. Some spreadsheets do this the other way round, which is a real source of disagreement.

Does it use eval?

No. The expression is tokenised and evaluated with the shunting-yard algorithm, because handing arbitrary text to the JavaScript engine is not a sensible trade for a calculator.