Percentage Calculator

A percentage calculator works out what one number is as a percentage of another — for example, 25 out of 200 is 12.5%. A percentage is just a part expressed out of 100, which is what lets you compare quantities of completely different sizes: a mark out of 75, a discount on a price, and a share of a population all become directly comparable once they are percentages. Enter the part and the whole and the answer appears as you type. Results are rounded to two decimal places, so a third shows as 33.33%, and figures above 100% are allowed — 300 out of 200 is 150%. Everything runs in your browser.

How to use it

1. Enter the value (the part) and the total (the whole).
2. The percentage is calculated the moment you finish typing.
3. Swap the numbers to answer a different question — the result updates live.
4. For a percentage increase, enter the change as the value and the starting number as the total: going from 200 to 250 is a change of 50, and 50 out of 200 is a 25% rise.

Examples

• 25 out of 200 = 12.5%.
• A score of 68 out of 75 = 90.67%.
• A rise from 200 to 250: enter 50 as the value and 200 as the total → 25%.
• 300 out of 200 = 150% — a percentage is not capped at 100.

Frequently asked questions

How do I calculate a percentage of a number?

Divide the part by the whole, then multiply by 100. For example, 25 out of 200 is (25 ÷ 200) × 100 = 12.5%. To find a percentage of a number instead — say 15% of 400 — multiply: 400 × 15 ÷ 100 = 60.

How do I work out a percentage increase?

Subtract the old value from the new value, divide by the old value, then multiply by 100. If a price rises from 200 to 250, that's (250 − 200) ÷ 200 × 100 = 25% increase.

What is the percentage formula?

The core formula is (part ÷ whole) × 100. Rearranged, part = percentage × whole ÷ 100, and whole = part × 100 ÷ percentage. All three answer different everyday questions.

Can I calculate reverse percentages?

Yes. If a number is already a percentage of an unknown total — for example, 30 is 15% of what? — divide the part by the percentage and multiply by 100: 30 × 100 ÷ 15 = 200.

What is the difference between percent and percentage points?

They measure different things, and headlines mix them constantly. If a rate moves from 5% to 6%, that is a rise of one percentage point — and it is also a 20% increase, because one is a fifth of five. Both statements describe the same change and both are correct. Use percentage points when you are comparing two percentages with each other, and percent when you are describing how far something moved from where it started. A charge 'up 20%' and a charge 'up 20 points' are very different claims.

Why does a 20% fall need a 25% rise to recover?

Because each percentage is taken from a different starting number. Take 100, cut it by 20% and you have 80. Getting back to 100 means adding 20 — and 20 out of 80 is 25%, not 20%. The trap runs the other way too: a 20% rise followed by a 20% fall leaves you at 96, not 100. Percentage changes never cancel out, which is why something down 50% and then up 50% is still down a quarter.

How do I work out a percentage in my head?

Break it into pieces you can do. Ten per cent is the number with the decimal point moved one place left, and the rest is built from that: 5% is half of 10%, 20% is double it, 15% is 10% plus half again. For 15% of 840, take 84, add 42, and you have 126. Swapping the two sides helps as well — 8% of 50 is the same as 50% of 8, which is 4, because multiplication does not care about the order.