Percentage calculator guide

How to use the Percentage Calculator

The Percentage Calculator handles the percentage questions people ask most often: percent of a number, what percent one number is of another, percentage increase or decrease, adding or subtracting a percent, and reverse percentage problems.

Open the percentage calculator

Quick start

Choose the percentage question you want to answer.
Enter the numbers shown for that mode.
Press Calculate percentage to get the answer.
Review the formula line and steps if you want to check the work.
Use examples, recent answers, or Copy answer while comparing values.

Choosing the right mode

Percent of a number: use this for questions like 20% of 80.

What percent: use this for questions like 25 is what percent of 200.

Percentage change: use this to compare an original value and a new value.

Add or subtract percent: use this for discounts, markups, tax, tips, or growth.

Reverse percent: use this when you know the part and the percentage but need the original whole.

Percentage examples

20% of 80 Turns 20% into 0.20, then multiplies by 80 to get 16.

25 is what % of 200 Divides 25 by 200, then multiplies by 100 to get 12.5%.

160 to 116 Finds a decrease of 44, then compares it with 160 to get 27.5% decrease.

120 plus 25% Finds 25% of 120, then adds 30 to get 150.

30 is 15% of what? Divides 30 by 0.15 to get 200.

Examples from the percentage calculator

Find percent of a number 20% of 80

Find what percent 25 is what % of 200

12.5%

Find percentage change 160 to 116

27.5% decrease

Discounts, tips, and markups

For a discount, choose Add or subtract percent, enter the original price, enter the percentage, and choose Decrease. For tax, tips, markup, or growth, use the same mode and choose Increase.

The result shows the final value. The formula line also shows the amount added or subtracted, which makes it easier to check the math.

Common mistakes to check

If you are finding what percent one number is of another, the whole value cannot be zero. If you are finding percentage change, the original value cannot be zero because the calculator has nothing to compare against.

For reverse percentages, the percentage cannot be zero. A question like "30 is 0% of what?" does not have one useful original whole.

History, privacy, and copying

Recent percentage answers stay visible in the current page while you work. This is useful when comparing discounts, prices, growth rates, or percentage changes. The history is kept only in the current browser tab and is not sent to a server.

Copy answer copies the displayed answer to your clipboard so you can paste it into notes, homework, a spreadsheet, or a message.