Percentage Increase / Decrease Calculator

Calculate the percentage change between an old and a new value.

Old value

New value

Quick answer: Percentage change = (new − old) ÷ old × 100. A positive result is an increase, a negative result is a decrease.

Worked example

A price rises from 80 to 100. The change is (100 − 80) ÷ 80 × 100 = 25% up. If it then falls from 100 back to 80, the drop is 20%, not 25%, because the drop is measured against the higher starting number.

How to use it

Enter the old (starting) value.
Enter the new value.
A plus sign means an increase and a minus sign means a decrease.

Common mistakes

Dividing by the new value instead of the old one.
Assuming a rise of X% followed by a fall of X% returns you to the start. A 50% rise then a 50% fall leaves you at 75, not 100.

Helpful tips

Percentage points and percent are different. Going from 4% to 6% is 2 percentage points, but a 50% increase.

Read the guide

How to Calculate Percentage Increase and DecreaseThe simple formula for percentage change, plus why a rise and a fall of the same percentage do not cancel out.

Frequently asked questions

How do I calculate percentage increase?

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

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