Percentage Calculator
Three tools in one: percent of a number, percentage ratio, and percentage change.
What is X% of Y?
X is what percent of Y?
Percentage increase / decrease
The three percentage formulas
Percent of a number: multiply the number by the percentage and divide by 100. So 15% of 200 = 200 × 15 ÷ 100 = 30. Use this for discounts, tips, tax and commission.
Percentage ratio: divide the part by the whole and multiply by 100. Scoring 30 out of 120 means 30 ÷ 120 × 100 = 25%. Use this for exam marks, market share and progress tracking.
Percentage change: subtract the old value from the new, divide by the old value, and multiply by 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = a 25% increase. Use this for price changes, salary raises and growth rates.
Frequently asked questions
What's the difference between percentage change and percentage points?
If a rate moves from 10% to 15%, it increased by 5 percentage points but by 50 percent (5 is half of 10). News reports often mix these up.
How do I calculate a discount price quickly?
A 20% discount means you pay 80%. Multiply the price by 0.8 — a 250 item at 20% off costs 250 × 0.8 = 200.
Why is a 50% loss not undone by a 50% gain?
Percentages compound from the current value. Dropping 100 → 50 is −50%, but recovering 50 → 100 requires +100%, because the base is now smaller.