％ Percentage Calculator

Free online percentage calculator

This percentage calculator solves the three questions people ask most often: what is a certain percent of a number, what percent one number is of another, and by what percent a value has increased or decreased. Type your numbers into the section you need, click Calculate, and see the answer immediately. It is handy for discounts, taxes, tips, grades, test scores, salary changes, statistics and everyday budgeting.

The three calculators

• What is X% of Y? Use it to find a part of a number, such as a 15% discount on 80.
• X is what percent of Y? Use it to turn two numbers into a percentage, such as scoring 42 out of 60 on a test.
• Percentage change from X to Y: Use it to measure growth or decline, such as a price moving from 50 to 65.

The formulas

• X% of Y = (X divided by 100) multiplied by Y
• X is what percent of Y = (X divided by Y) multiplied by 100
• Percentage change = ((new value minus old value) divided by the absolute old value) multiplied by 100

Worked examples

• Discount: 20% of 150 is 30, so the discounted price is 120.
• Test score: 42 out of 60 is (42 divided by 60) multiplied by 100, which is 70%.
• Price change: from 50 to 65 is an increase of 30%.
• Decrease: from 80 to 60 is a decrease of 25%.

Common mistakes

• An increase of 50% followed by a decrease of 50% does not return you to the start. Starting at 100, you reach 150, then 75.
• Percentage points and percent are different. Going from 10% to 12% is a rise of 2 percentage points, but a 20% increase in the rate.
• The starting value for percentage change is the old number, not the new one. Mixing them up gives a different answer.
• Percent change from zero cannot be calculated, because you would divide by zero.

Frequently asked questions

How do I calculate a discount?

Find the percent of the price with the first calculator and subtract it from the original price.

How do I add a percentage, like tax, to a price?

Calculate the percent of the price with the first calculator and add that amount to the price.

Why does it say the starting value cannot be zero?

Percentage change compares the new value with the old one. If the old value is zero, the change cannot be expressed as a percent.

Are my numbers saved?

No. Calculations happen in your browser and nothing is stored or sent to a server.