Percentage Calculator
Find a percentage of a number, work out what percent one number is of another, find the whole from a part, or calculate a percentage increase or decrease. Results update as you type.
Choose what you want to find
What is P% of N?
X is what percent of Y?
X is P% of what number?
What is X increased or decreased by P%?
Result
How the percentage formula works
result = (percentage ÷ 100) × number
Example: 20% of 80 → (20 ÷ 100) × 80 = 16
percentage = (X ÷ Y) × 100
Example: 25 out of 50 → (25 ÷ 50) × 100 = 50%
whole = (X × 100) ÷ percentage
Example: 10 is 5% of what → (10 × 100) ÷ 5 = 200
result = X × (100 ± percentage) ÷ 100
Example: 500 increased by 10% → 500 × 110 ÷ 100 = 550
Worked examples
- A $120 jacket is discounted 25%. The discount is 120 × 25 ÷ 100 = $30, so the sale price is $90.
- You scored 42 out of 60 on a test. That is (42 ÷ 60) × 100 = 70%.
- A fund that was $8,000 is now $9,200. That is an increase of (9,200 − 8,000) ÷ 8,000 × 100 = 15%.
- 12.5 is 25% of some budget. The budget is (12.5 × 100) ÷ 25 = $50.
Things to keep in mind
Percentage vs. percentage points
If a rate moves from 10% to 12%, that is a change of 2 percentage points, but a 20% relative increase (2 ÷ 10 × 100). The two are easy to mix up in news headlines and reports.
Rounding
Percentages are often rounded to one or two decimal places for readability. For exact totals (tax, splits, discounts), keep more decimal places until the final step.
Negative percentages
A negative result in the increase/decrease mode means the value went down rather than up — it is the same as choosing “Decrease”.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 200 is (15 ÷ 100) × 200 = 30.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 18 out of 24 is (18 ÷ 24) × 100 = 75%.
How do I reverse a percentage to find the original number?
Divide the known part by the percentage (as a decimal) rather than multiplying. If 10 is 5% of a number, the number is 10 ÷ 0.05 = 200.
What is the difference between percentage increase and percentage change?
Percentage increase and decrease assume you already know the direction. Percentage change (and percentage difference) calculate the direction and size together from two values — see the related calculators below.
Related calculators
For information only. Double-check important calculations (tax, grades, financial decisions) before relying on them.
Last updated: October 18, 2026