Percentage Calculator

1. Pick the question you want to answer from the list.
2. Type your two numbers. The labels change to match the question.
3. Read the answer, the steps, and the extra details below it.

A percentage is a number out of 100. The word percent means "per hundred." So 20 percent means 20 out of every 100, which is the same as the fraction 20/100 or the decimal 0.20.

Percentages make it easy to compare parts of different wholes. A test score of 45 out of 50 and 90 out of 100 look different, but both are 90 percent.

Every percentage question uses one of these four formulas. Turn the percent into a decimal by dividing by 100 first.

Step-by-step guides: how to calculate a percentage and the percentage change formula.

Where:

• P = the percent
• N or Y = the whole number
• X = the part
• old and new = the starting and ending values

A 30% off sale on a $200 jacket saves 0.30 x 200 = $60, so you pay $140. For sale prices, the percent off calculator does both steps at once.

The most-searched "what is X% of Y" questions, worked out. For any other pair, use the calculator above.

A percent change compares a new value with the old one. A percentage point change is the plain difference between two percentages.

If a savings rate goes from 2% to 3%, it rose by 1 percentage point. But compared with where it started, it rose by 50 percent. News stories mix these up often, so check which one is meant.

Why Equal Changes Do Not Cancel

A 50% rise from 100 gives 150. A 50% fall from 150 gives 75, not 100. Each change uses a different starting value.

Adding a Percent

To add 15% to a number, multiply by 1.15. To remove 15%, multiply by 0.85.

For a full breakdown, use the percentage increase calculator.

Shopping and Discounts

Find the savings and sale price for any discount.

Tips and Tax

Work out a 15% or 20% tip, or sales tax on a bill.

Grades and Scores

Turn a test score into a percent, such as 42 out of 50 = 84%.

Money and Prices

Measure a raise, a rent increase or a price drop as a percent change.

The method is the same in every language: multiply the number by the percent, then divide by 100.

1. Confusing Percent of with Percent Off

30% off means you pay 70% of the price, not 30%.

2. Using the Wrong Base

Percent change always divides by the starting value, not the new one.

3. Forgetting to Divide by 100

Use 0.20 for 20% in a formula, not 20.

4. Adding Percentages with Different Bases

Two discounts of 20% and 10% are not 30% off. They give 28% off in total.

The math is exact. Answers show up to 4 decimal places.

20% of 200 is 40. Multiply 200 by 0.20.

10% of 5,000 is 500. Move the decimal one place to the left.

Divide the percent by 100, then multiply by the number. For 30% of 300, that is 0.30 x 300 = 90.

Divide the part by the whole, then multiply by 100. For 50 out of 200, (50 / 200) x 100 = 25%.

Subtract the old value from the new one, divide by the old value, then multiply by 100. A positive answer is an increase.

Percent of gives a part of the number. Percent off subtracts that part. 30% off means you pay 70% of the price.

Each change uses a different base. Up 50% from 100 gives 150, then down 50% gives 75, not 100.

Divide by 100. So 25% is 0.25 and 7.5% is 0.075.

Divide the part by the percent as a decimal. If 40 is 20% of a number, the number is 40 / 0.20 = 200.

It is the plain difference between two percentages. Going from 2% to 3% is 1 percentage point, but a 50% increase.

• Percentages (Math Is Fun).
• Percentage change (Math Is Fun).
• The meaning of percent (Khan Academy).