X is what % of Y

Find what percentage one number is of another. Example: 25 is 50% of 50

% change from X to Y

Calculate the percentage increase or decrease. Example: 80 → 100 is a 25% increase

Increase / decrease X by Y%

Add or subtract a percentage. Example: 200 increased by 15% = 230

Y is X% of what

Find the original value when you have a percentage and the result. Example: 50 is 25% of 200