A clean four-function calculator with percentage and memory keys.
This calculator performs standard four-function arithmetic on two numbers. The optional percent mode follows the convention of physical calculators: for addition and subtraction the second number is treated as a percentage of the first (so 200 + 15% adds 30, not 0.15); for multiplication and division it divides by 100 first.
Addition
Result = A + B
Percent-of add
Result = A + (B% × A) when percent mode is on
It converts the second number into a percentage of the first before adding. So 200 + 15% means 200 + (15% of 200) = 200 + 30 = 230 — the same as most physical calculators and spreadsheets.
The result is a repeating decimal (0.333…). The calculator shows up to 10 decimal places so you can see the precision. For exact results, use the Fraction Calculator instead.
This calculator is intentionally designed for one operation at a time. For chained expressions, use the Scientific Calculator which supports a full expression parser.