Percentage Calculator
Work out what X% of a value is — discounts, tips, statistics, anything.
- Result30.00
Inputs used
- Percentage20 %
- Of the value150
About this calculator
To take a percentage of a value, divide the percentage by 100 and multiply: 20% of 150 is 150 × 0.20 = 30. The word percent literally means "per hundred", so 20% is just the fraction 20/100.
Two quick mental tricks: 10% is the value with the decimal point moved one place left, and any percentage can be built from that — 5% is half of 10%, 20% is double it. And X% of Y always equals Y% of X: 8% of 25 is the same as 25% of 8, which is often easier to see at a glance.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply: 20% of 150 is 0.20 × 150 = 30. The same value comes from 150 × 20 ÷ 100 — whichever order is easier to do in your head.
How do I work out what percentage one number is of another?
Divide the part by the whole and multiply by 100: 30 out of 150 is 30 ÷ 150 × 100 = 20%. For the percentage change between two values (a rise or fall), use the percentage change calculator instead.
What is the fastest mental shortcut?
Build everything from 10%. Move the decimal one place left for 10%, halve that for 5%, double it for 20%. And remember X% of Y equals Y% of X — 4% of 50 feels hard, but 50% of 4 is instantly 2.
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Results are informational only — not financial, medical or legal advice.