Scientific Calculator

Every expression you type is parsed before it is solved. The calculator reads the line character by character into numbers, operators, functions, and constants, then reorders them with the shunting-yard algorithm so precedence is settled before any arithmetic happens. Parentheses bind first, then functions, then powers, then multiplication and division, and finally addition and subtraction. Powers stay right-associative, so 2^3^2 gives 512 rather than 64, matching how a handheld calculator behaves.

That parsing step is also a safety decision. The input is never handed to the JavaScript engine to run, so nothing typed into the display can execute as code. Anything the parser does not recognise is rejected instead of guessed at.

Trigonometry respects the angle switch. In degrees, arguments to sine, cosine, and tangent are converted to radians before the calculation, and results from the inverse functions are converted back, so sin(30) returns exactly 0.5. In radian mode the values pass through untouched. Factorials are computed as whole-number products and refuse negative or fractional input rather than returning something meaningless.

Results are formatted for reading, not for maximum digits. Whole numbers stay whole, ordinary decimals are trimmed to twelve significant figures to hide floating-point noise, and anything above a trillion or below a billionth switches to exponential form. Each answer you confirm is kept in the history list, where a tap drops it back into the input. Nothing is sent to a server.