Percentage Calculator
X% of Y, percentage change, add or subtract a percent. All in one place.
Percentage calculator formulas
X% of Y: (X ÷ 100) × Y. % change: ((New − Old) ÷ Old) × 100. Add X%: Y × (1 + X/100). Subtract X%: Y × (1 − X/100).
Common percentage conversions
| Fraction | Percent | Fraction | Percent |
|---|---|---|---|
| 1/4 | 25% | 3/4 | 75% |
| 1/2 | 50% | 1/5 | 20% |
| 1/3 | 33.33% | 2/3 | 66.67% |
| 1/10 | 10% | 1/8 | 12.5% |
| 1/20 | 5% | 1/100 | 1% |
When to use a percentage calculator
Percentages appear in tips (15%, 20%), sales tax, pay raises (3% increase), discounts, tax rates, and investment returns. Use our tip calculator, sales tax calculator, or pay raise calculator for those specific cases.
Common Questions About Percentages
How do I calculate X% of Y?
Convert the percentage to a decimal (divide by 100) and multiply by Y. X% of Y = (X ÷ 100) × Y. Example: 15% of $80 = 0.15 × 80 = $12. Or: 20% of 250 = (20 ÷ 100) × 250 = 50. Use the "X% of Y" tab in the calculator above for instant results.
How do I calculate percentage increase or decrease?
Percentage change = ((New − Old) ÷ Old) × 100. For an increase: $100 → $120 = (20 ÷ 100) × 100 = 20% increase. For a decrease: $100 → $80 = (-20 ÷ 100) × 100 = -20% (or 20% decrease). This formula works for prices, salaries, and any numeric change. Use the "% change" tab in the calculator.
How do I add or subtract a percentage?
Add X%: multiply by (1 + X/100). $100 + 8% = $100 × 1.08 = $108. Subtract X%: multiply by (1 − X/100). $100 − 15% = $100 × 0.85 = $85. Useful for discounts, sales tax, markups, and tips.
What's the difference between percentage point and percent?
A percentage point is the absolute difference between two percentages. If a rate goes from 10% to 15%, that's a 5 percentage point increase. A percent (relative change) would be (15 − 10) ÷ 10 = 50%—the rate increased by 50% of its original value. In news and finance, "the Fed raised rates by 0.25 percentage points" means the rate itself went up 0.25%, not 0.25% of the rate.
How do I reverse a percentage (find the original before a markup or discount)?
If you have a final amount after a percentage change, divide by the multiplier. After 20% markup: $120 ÷ 1.20 = $100 original. After 15% discount: $85 ÷ 0.85 = $100 original. For "what was the price before tax?" use our sales tax calculator in remove-tax mode.