How it works
Formulas
X% of Y = X ÷ 100 × Y. X as a percent of Y = X ÷ Y × 100. Percent change = (new − old) ÷ |old| × 100; a negative result is a decrease.
Frequently asked questions
Is a 50% increase followed by a 50% decrease back to the start?
No. 100 → 150 (+50%) → 75 (−50%). Percent changes apply to different bases.