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Percentage Calculator

Solve the three most common percentage problems: a percentage of a number, what percent one number is of another, and percentage change.

What is X% of Y?

Percentage (%)

Of this number

X is what percent of Y?

Number X

Number Y

Percentage increase or decrease

From (old value)

To (new value)

How to use the percentage calculator

Pick the question that matches your problem.
Enter the two numbers.
Press Calculate to see the answer.

How it works

X% of Y = X ÷ 100 × Y.

X is what percent of Y = X ÷ Y × 100.

Percentage change = (new value − old value) ÷ old value × 100. A positive result is an increase and a negative result is a decrease. The change is always measured against the old value.

Example

15% of 240 is 36. 36 is 15% of 240. A change from 80 to 100 is an increase of 25%.

Frequently asked questions

How do I calculate a percentage increase?

Subtract the old value from the new value, divide by the old value and multiply by 100.

Why is a 50% increase followed by a 50% decrease not back to the start?

Because the second change is measured against the larger number. 100 up 50% is 150, and 150 down 50% is 75.

Can I use negative numbers?

Yes for most fields. Percentage change from zero is undefined, so the calculator asks for a non-zero old value.