Percentage Calculator
Work out percentages, ratios and percentage change in one place — no formulas to remember.
Calculation
Finds a percentage of a value — useful for tips, discounts and shares.
Result
30
Percentages turn up everywhere: a 20% tip, a 15%-off sale, an exam score, a pay rise, or the return on an investment. This free percentage calculator handles the three questions people ask most — what is X% of a number, what percentage one number is of another, and how much a value has gone up or down. Type your numbers and the answer appears instantly, along with a plain-English sentence so you can see exactly what it means. No sign-up, no app, nothing to install.
How to calculate a percentage
A percentage is just a fraction out of 100. Every calculation on this page comes down to one of three simple formulas, depending on what you already know and what you want to find.
% of a number: result = (X ÷ 100) × Y
X is what % of Y: result = (X ÷ Y) × 100
% change from X to Y: result = ((Y − X) ÷ X) × 100
For percentage change, a positive result is an increase and a negative result is a decrease. For example, going from 200 to 250 is a 25% increase, while going from 250 to 200 is a 20% decrease — the two are not the same, because the starting number is different each time.
Frequently asked questions
How do I calculate a percentage of a number?+
Divide the percentage by 100, then multiply by the number. For example, 15% of 200 is (15 ÷ 100) × 200 = 30. Use the first mode above and it does this for you automatically.
How do I find what percentage one number is of another?+
Divide the first number by the second, then multiply by 100. For example, 30 out of 200 is (30 ÷ 200) × 100 = 15%. Switch to the second mode to calculate this instantly.
How do I calculate a percentage increase?+
Subtract the original value from the new value, divide by the original value, then multiply by 100. Going from 200 to 250 is ((250 − 200) ÷ 200) × 100 = 25% increase. The third mode labels the result as an increase or decrease for you.
Why isn't a 25% increase cancelled out by a 25% decrease?+
Because the base changes. A 25% increase on 200 gives 250, but a 25% decrease on 250 gives 187.5, not 200 — the decrease is applied to a larger number. That's why raising then dropping a value by the same percentage never brings you back to where you started.
What happens if I leave a field blank or divide by zero?+
The calculator shows a dash (—) instead of an error. Percentages that would require dividing by zero — such as asking what percent a number is of zero — have no defined answer, so nothing is shown until you enter valid values.
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