Five percentage calculators in one: percent of, percent of what, percent change and more.
X% of Y = X ÷ 100 × Y. So 15% of 200 is 30. To find what percent 30 is of 200, divide: 30 ÷ 200 × 100 = 15%.
A percentage is a fraction out of 100. This page has five calculators for the questions people ask most: what is X% of Y; X is what percent of Y; X is Y% of what number; the percentage change between two values; and increasing or decreasing a number by a percentage. Each shows the working so you can learn the method.
Percentages are everywhere — discounts, interest, marks, tax and statistics. For shopping see the Percent Off Calculator and Discount Calculator; for comparing a measured value with a true value use the Percent Error Calculator.
The calculator applies the standard method step by step.
| Question | Answer |
|---|---|
| 5% of 200 | 10 |
| 15% of 200 | 30 |
| 25% of 200 | 50 |
| 50% of 200 | 100 |
| 12.5% of 200 | 25 |
| Percentage | Fraction | Decimal | Of 80 |
|---|---|---|---|
| 10% | 1/10 | 0.1 | 8 |
| 12.5% | 1/8 | 0.125 | 10 |
| 20% | 1/5 | 0.2 | 16 |
| 25% | 1/4 | 0.25 | 20 |
| 33⅓% | 1/3 | 0.3333 | 26.67 |
| 50% | 1/2 | 0.5 | 40 |
| 75% | 3/4 | 0.75 | 60 |
| 100% | 1 | 1 | 80 |
Divide the percentage by 100 and multiply by the number. 15% of 200 = 0.15 × 200 = 30.
Divide the first number by the second and multiply by 100. 30 is 15% of 200.
Subtract the old value from the new, divide by the old value and multiply by 100. From 80 to 100 is a 25% increase.
Because the base changes. 100 up 25% is 125; 125 down 20% is 100 — the percentages differ since each is taken from a different starting value.
Multiply by (1 + percentage ÷ 100). To add 15% to 200: 200 × 1.15 = 230.
The simple difference between two percentages. Going from 10% to 12% is a 2 percentage-point rise but a 20% relative increase.
It uses the standard method: X% of Y = X ÷ 100 × Y change = (new − old) ÷ |old| × 100 The full working and a worked example are shown on this page.
Decimal results use standard double-precision arithmetic (about 15–16 significant digits). Tools that work with whole numbers — big numbers, factors, bases, combinations — use exact integer arithmetic, so no digits are lost.
Yes for checking your work and learning the method. The steps and formula are shown so you can understand the answer, but follow your teacher's rules about calculators in exams.
No. Everything is calculated in your browser and nothing you enter is uploaded or saved.
