About this percentage calculator
Three everyday percentage calculations in one place: find X% of Y, find what percent X is of Y, and find the percentage change from X to Y. Results update live as you type, and the change rate is colour-coded so increases and decreases are obvious at a glance.
The formulas are transparent: percent = value × rate ÷ 100, share = part ÷ total × 100, change = (new − old) ÷ old × 100. Negative and decimal inputs are supported, and a zero divisor is reported clearly. Every calculation runs locally in your browser.