Percentage of a Number Calculator
Find what X% of any number is, or calculate what percentage one number is of another. All three percentage formulas in one place, with step-by-step working shown.
What is X% of a number?
Enter a percentage and a number to find the result. For example: what is 20% of 150?
X is what percentage of Y?
Enter two numbers to find what percentage the first is of the second.
Find the whole: X is P% of what number?
Enter a value and a percentage to find the total it represents a percentage of.
The three core percentage formulas
Every percentage problem is one of three types, each with its own formula.
1. Find X% of a number
Formula: Result = Number × (Percentage ÷ 100). What is 20% of 150? 150 × 0.20 = 30.
2. Find what percentage X is of Y
Formula: Percentage = (X ÷ Y) × 100. What percentage is 30 of 150? (30 ÷ 150) × 100 = 20%.
3. Find the whole when you know a part and a percentage
Formula: Whole = Part ÷ (Percentage ÷ 100). 30 is 20% of what? 30 ÷ 0.20 = 150.
Real-world examples
Tax: 8.5% of $120 = $120 × 0.085 = $10.20 tax. Survey: 45 out of 300 people said yes — what percentage? (45 ÷ 300) × 100 = 15%. Savings goal: you saved $400, which is 25% of your target — what's the target? $400 ÷ 0.25 = $1,600.
Frequently asked questions
20% of 50 = 50 × 0.20 = 10.
15% of 200 = 200 × 0.15 = 30.
(45 ÷ 180) × 100 = 25%. So 45 is 25% of 180.
5% of 1,000 = 1,000 × 0.05 = 50.
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