Common percentage calculations
Percentage calculators handle everyday math like discounts (20% off $150), tips (18% of $42), sales increases, or test scores.[web:537][web:538][web:544]
Quick formulas
- What is X% of Y?
(X/100) × Y— 15% of 200 = 30[web:541] - X is what % of Y?
(X/Y) × 100— 30 is 15% of 200[web:539] - Increase/Decrease:
((new-old)/|old|) × 100— $100 to $120 = +20%[web:542][web:545]