Three common percentage problems, solved instantly — pick the one you need below.
Last updated: September 2026
What % is X of Y — use this to find what portion one number makes up of another, like calculating a test score or commission rate.
% increase / decrease — use this to see how much something changed, like a price hike, salary raise, or sales drop between two periods.
Add / subtract % — use this to apply a percentage directly to a number, like adding 17% sales tax or calculating a 20% discount price.
Subtract the original value from the new value, divide by the original value, then multiply by 100. Use the "% increase/decrease" mode above to do this instantly.
A change from 20% to 25% is a 5 percentage point increase, but a 25% relative increase (5 ÷ 20 × 100). These two ways of describing the same change are often confused in reporting.