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Three calculators in one. Results update as you type.
Percentage Calculator
Solve the three everyday percentage questions without a formula: what is 15% of 80, what percent is 12 of 48, and how much did a value go up or down. Everything runs in your browser.
-X% of Y
-X as a percent of Y
-Change from X to Y
The three percentage formulas
Almost every percentage question is one of three shapes. This page solves all three side by side:
- X% of Y = Y × X ÷ 100. Use it for tips, discounts, tax and commission.
- X as a percent of Y = X ÷ Y × 100. Use it for test scores, budget shares and completion rates.
- Percentage change = (new − old) ÷ |old| × 100. A positive result is an increase, a negative result is a decrease.
Worked examples
15% of 80: 80 × 15 ÷ 100 = 12.
12 out of 48: 12 ÷ 48 × 100 = 25%.
50 to 65: (65 − 50) ÷ 50 × 100 = +30%. Going back from 65 to 50 is only −23.08%, because the starting point is larger.
Percent change vs percentage points
If an interest rate moves from 4% to 5%, it rose by 1 percentage point but by 25 percent in relative terms. News reports often mix the two. Use the third calculator for the relative change, and simple subtraction for percentage points.
Common mistakes
A 20% drop followed by a 20% rise does not bring you back to the start: 100 becomes 80, then 96. Percentages always apply to the current base, so sequential changes multiply rather than add. To reverse a percentage increase, divide by (1 + rate) instead of subtracting the same percentage.
Planning estimate only. Results use the list prices shown and may differ from your actual bill. Terms
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 15% of 80 is 80 × 15 ÷ 100 = 12. The first calculator on this page does this for you.
How do I work out what percent one number is of another?
Divide the part by the whole and multiply by 100. 12 out of 48 is 12 ÷ 48 × 100 = 25%.
How is percentage increase calculated?
Subtract the old value from the new value, divide by the old value, and multiply by 100. Going from 50 to 65 is (65 − 50) ÷ 50 × 100 = 30%.
Why is a 50% loss not undone by a 50% gain?
Because the second percentage applies to a smaller base. 100 minus 50% is 50, and 50 plus 50% is only 75. You would need a 100% gain to get back to 100.
What is the difference between percent and percentage points?
Percentage points are the plain difference between two percentages (4% to 5% is 1 point). Percent change is the relative difference (4% to 5% is a 25% increase).