All three modes use the same relationship, rearranged:
- X% of Y = (X ÷ 100) × Y
- X is what % of Y = (X ÷ Y) × 100
- X is P% of what = X ÷ (P ÷ 100)
A percentage is simply a ratio scaled to 100 — "per cent" literally means "per hundred".
Math Calculators
Percentage Calculator
Percentages express a number as a fraction of 100 — they're how we talk about discounts, marks, interest rates and growth. This calculator answers the three percentage questions people ask most: what is X% of a number, what percent is one number of another, and what number is X when you only know the percentage.
Answer
40.00
How it works
Worked example
- 20% of 200 = (20 ÷ 100) × 200 = 40
- 45 is what % of 150? = (45 ÷ 150) × 100 = 30%
- 60 is 15% of what number? = 60 ÷ 0.15 = 400
Understanding your results
The answer is shown to two decimal places — enough precision for marks, discounts and everyday math without false exactness. If you're working with money, round the final result to the nearest rupee; banks and shops don't transact in paise fractions of a percent.
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Frequently asked questions
Divide your total obtained marks by the maximum marks, then multiply by 100. For example, 432 out of 500 = (432 ÷ 500) × 100 = 86.4%.
A change from 20% to 25% is a 5 percentage-point increase, but a 25% relative increase (5 ÷ 20 × 100). Mixing these up is the most common percentage mistake in news and reports.
Divide by the percentage as a decimal. If 60 is 15% of some number, that number is 60 ÷ 0.15 = 400. Use the third mode of this calculator.
Percentages compare to a base of 100, but the value can exceed the base. 150% of 200 is 300 — common when describing growth ("sales grew to 150% of last year").
Content last reviewed on 2026-10-06.