Calculate percentages easily with multiple calculation modes.
Percentage calculations are among the most frequent everyday math operations: tip calculations, sale discounts, tax computations, growth rates, exam scores, mortgage rates, and a long list of others. The math is simple — multiply by the percentage as a decimal — but there are several distinct percentage operations and confusing them produces wrong answers. The calculator separates them clearly so each scenario has its own clear input form.
Common percentage operations: what is X% of Y (apply a percentage to a number); X is what percent of Y (find the percentage one number represents of another); what is the percentage change from X to Y (increase or decrease as a percent); add or subtract X% from Y (apply a percentage adjustment to a base).
This tool offers each operation with labeled inputs so you can pick the right one for your situation. Calculations happen in your browser using basic arithmetic; no data is sent to any server.
Even people comfortable with mental math benefit from a calculator for percentage operations involving non-trivial values: 17% tip on $43.75, 22% off a $189 item, 8.875% sales tax on a $234.50 purchase. Hand calculation introduces arithmetic errors; a calculator gives exact results.
Percentage change is also commonly miscomputed. The percent change from 80 to 100 is +25%, not +20%; the percent change from 100 to 80 is -20%, not -25%. Asymmetry around the base value confuses many people. A calculator with explicit 'from' and 'to' fields removes the ambiguity.
Choose the operation, fill in two values, get the answer.
Each operation is straightforward arithmetic. X% of Y = (X/100) * Y. X is what percent of Y = (X/Y) * 100. Percentage change from X to Y = ((Y-X)/X) * 100. Add X% to Y = Y * (1 + X/100). Subtract X% from Y = Y * (1 - X/100).
Floating point limitations apply. Calculations involving long decimal repeats (1/3, 1/7, etc.) may show small rounding artifacts. Display precision is typically 2–4 decimal places, which masks the floating-point representation issues for normal use.
Negative inputs are accepted where mathematically meaningful. Percentage change of -20% (a decrease) is shown as a negative number. Adding negative percentages effectively subtracts.