Finding the Percent
Practise the reverse question — working out what percent one number is of another, like “15 is what percent of 60?”
Practice now
How to find what percent one number is
This is the reverse of finding a percent of a number. Here you know the part and the whole, and you want the percentage. The recipe: make a fraction, then turn it into a percent.
- Write the part over the whole as a fraction: 15 of 60 → 15/60.
- Divide to get a decimal: 15 ÷ 60 = 0.25.
- Multiply by 100 to get the percent: 0.25 → 25%.
Worked examples
Tips & common mistakes
The key is getting the part and whole the right way round — the part goes on top, the whole (the “of” number) on the bottom. Recognising simple fractions helps: 1/4 is 25%, 1/2 is 50%, 1/10 is 10%. Type just the number of percent.
- Flipping the fraction — the part goes over the whole, not the other way round.
- Stopping at the decimal and forgetting to multiply by 100.
- Reading the bigger number as the part when it’s actually the whole.
Frequently asked questions
How do you find what percent one number is of another?
Write the part over the whole as a fraction, divide to get a decimal, then multiply by 100. 15 of 60 = 15/60 = 0.25 = 25%.
Which number goes on top?
The part — the amount you’re measuring. The whole (the total, the “of” number) goes on the bottom.
How is this different from ‘percent of a number’?
That finds the part when you know the percent; this finds the percent when you know the part and whole. They’re reverse questions.
Any shortcuts?
Yes — recognise common fractions: 1/4 = 25%, 1/2 = 50%, 3/4 = 75%, 1/10 = 10%.
What grade is this?
It’s a grade 6–7 skill, part of working with ratios and proportions.
Keep practising
← All percentagesPercent of a numberSimplifying fractions6th grade math