Percentage Calculator

Quick answer

This calculator computes percentages instantly: 20% of 150 = 30.

Percent of a number, percent increase/decrease, and what percent one number is of another.

Figures are estimates from this calculator’s standard formula — adjust the inputs in the tool below for your exact number.

Common percentage examples

Question	Calculation	Answer
20% of 150	150 × 0.20	30
10% of 450	450 × 0.10	45
15% of 200	200 × 0.15	30
50% of 84	84 × 0.50	42
25% of 60	60 × 0.25	15

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How to Calculate a Percentage

part = (percent ÷ 100) × whole

A percent is a fraction of 100. To find a percent of a number, convert the percent to a decimal and multiply: 15% × 200 = 0.15 × 200 = 30. To find what percent X is of Y, divide: 45 ÷ 60 = 0.75 = 75%.

1
Pick the calculation type
Percent of a number, X as % of Y, or percent change.
2
Enter your two numbers
Example: 15 and 200.
3
Read the answer
15% of 200 = 30, shown with the full working.

Use Cases

Shopping Discounts

Calculate final prices after percentage discounts on products

Tax Calculations

Compute sales tax, VAT, or income tax amounts

Grade Conversions

Convert test scores to percentages for academic evaluation

Investment Returns

Calculate return on investment and portfolio performance

Tips

1
To find X% of Y, multiply Y by X and divide by 100
2
To find what percentage X is of Y, divide X by Y and multiply by 100
3
Percentage increase = ((New - Old) / Old) x 100
4
For reverse percentage, divide the part by the percentage and multiply by 100

Common Mistakes

Confusing percentage points with percentages - an increase from 10% to 15% is 5 percentage points but a 50% relative increase
Calculating discount from the discounted price instead of the original price
Adding percentages directly - two successive 10% increases equal 21%, not 20%
Forgetting that a 50% decrease requires a 100% increase to return to the original value

FAQs

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. Example: 20% of 150 = 150 × 20 ÷ 100 = 30.

What is 15% of 200?

15% of 200 = 30, because 200 × 0.15 = 30.

How do I calculate percentage increase between two numbers?

Increase % = (new − old) ÷ old × 100. Example: from 80 to 100 is a 25% increase.

What percent of 50 is 40?

Divide 40 by 50 and multiply by 100: 40 ÷ 50 × 100 = 80%.

How do I convert a fraction to a percentage?

Divide the numerator by the denominator and multiply by 100. Example: 3/4 = 0.75 = 75%.

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