Percentage Calculator
Five percentage calculators in one: percent of, what percent, percent change, increase and decrease.
How to use the Percentage Calculator
Pick what you want to find and enter X and Y. Results update instantly as you type.
Formula
X% of Y = X ÷ 100 × Y % change = (New − Old) ÷ |Old| × 100
Worked example
15% of 240 is 36. Going from 80 to 100 is a 25% increase.
Frequently asked questions
How do I calculate a percentage increase?
Subtract the old value from the new value, divide by the old value and multiply by 100.
Is a 50% drop reversed by a 50% gain?
No. 100 → 50 is −50%, but 50 → 100 is +100%.
Results are estimates for educational and planning purposes. Always confirm important financial, health or legal decisions with a qualified professional. Last reviewed 2026-09-27.