Scientific Calculator

When the simple calculator no longer cuts it, the Scientific Calculator takes over. It does not work key by key but evaluates a whole expression: you can write out a complete formula with brackets, several operations and functions and get exactly one result at the end. That is the way you know from physics or maths class, just without the expensive plastic device.

On board are the trigonometric functions sine, cosine and tangent along with their inverses, the base-10 and the natural logarithm, the square root, free powers via the caret sign, the square as its own key, the reciprocal and the factorial. There are also the constants Pi and Euler number e, which you can drop straight into your calculation.

For the angle functions there is a switch between degrees and radians, clearly visible at the top of the display. That is the difference where most mistakes happen in practice: the sine of 45 in degrees is something entirely different from in radians. The calculator always shows clearly which mode you are in, so you never accidentally calculate in the wrong one.

The four memory keys work like on a classic desktop calculator: store to memory, recall from memory, add to it and subtract from it. That lets you collect interim results without noting them down anywhere. A small M in the display reminds you that a value is currently in memory. There is also a history of recent calculations from which you bring back any expression with a click and reuse it.

Under the hood sits a clean formula parser, not a risky evaluation of arbitrary code. It handles implicit multiplication, so 2 Pi or 2(3) mean exactly what you expect, and it recognises signs and bracket structures correctly. If something does go wrong - the root of a negative number, the logarithm of zero, an undefined tangent point or mismatched brackets - you get no cryptic error but a clear message with a wink.

The whole calculator is keyboard-operable: digits, operators, brackets, caret for powers, the exclamation mark for factorial, Enter to evaluate and Escape to clear. Results are formatted with a comma or a dot depending on the language and announced for screen readers. Everything runs locally in the browser, with no account, no signup and without your calculations leaving the device.