Percentage Calculator

Answer the three everyday percentage questions in one place: a percent of a number, what percent one value is of another, and an increase or decrease by a percent. Fill in the values and press Calculate.

Written by TopicDrill Editorial Team·Updated June 2026

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How the percentage calculator works

Percentages all come back to the same idea: a part compared to a whole, scaled to 100. This tool packages the three questions people ask most. Pick a mode, type your numbers, and it applies the matching formula and shows the working so the answer is easy to check.

The donut chart turns the result into a picture. It shades the share you calculated against the rest of the base, which makes it quick to see whether an amount is a small slice or most of the total.

A quick example

Say a $150 jacket is marked down by 20 percent. Using the first mode, 20 percent of 150 is 30, so the discount is $30 and you pay $120. Switch to the third mode, enter a start of 150 and a change of negative 20 percent, and you get the same $120 final price directly.

Things to keep in mind

Order matters with stacked percentages: a 20 percent rise followed by a 20 percent fall does not return you to the start, because each step works on a different base. For more on the underlying idea, see this overview of percentages. To compare two figures over time, use our percentage change calculator.

Frequently asked questions

How do I find a percent of a number?

Divide the percent by 100 and multiply by the number. For example 20 percent of 150 is 0.20 times 150, which equals 30. This calculator does that for you when you pick the first option.

How do I work out what percent one number is of another?

Divide the part by the whole and multiply by 100. If you scored 45 out of 180, that is 45 divided by 180 times 100, which equals 25 percent. Choose the second option to calculate this directly.

How do I increase or decrease a value by a percent?

Multiply the value by 1 plus the percent divided by 100 to increase it, or by 1 minus the percent over 100 to decrease it. To add 15 percent to 200, multiply by 1.15 to get 230. Enter a negative percent to apply a decrease.

What is the difference between percent and percentage points?

A percent describes a proportion of a base value, while a percentage point is the plain difference between two percentages. Going from 10 percent to 12 percent is a rise of 2 percentage points but a 20 percent relative increase in the rate.

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