Percentage Increase Calculator

This percent increase calculator shows how much a number grew, or fell, as you type. Enter the old number and the new one to get the answer and the working.

The formula

Percentage increase compares a new number with the number you started from. Divide the change by the starting value, then multiply by 100:

((new − original) ÷ original) × 100

If the result is negative, the value fell. This page labels that result as a decrease rather than hiding the sign. Adding a percent, and reversing a percent, use the two other modes above. Comparing two numbers that have no before-and-after order is a different question, answered on the percentage difference page.

How to use the percent increase calculator

The calculator has three modes, one for each way people usually come at this question:

Find percent compares two numbers. Use it when you know the before and the after, such as last year's and this year's rent.
Add percent applies a rate you already know. Use it to see what a 4% raise or a 7.5% price hike does to a figure.
Reverse works backward from a final number. Use it when a receipt shows the price after an increase and you want the price before it.

Each answer comes with the exact formula filled in with your numbers, so you can copy the working into homework, a report, or an email. The Copy link button saves your inputs in the address, which makes it easy to share a result with someone else.

Common percent increases at a glance

Old value	New value	Percent increase	Where you might see it
$3.50	$3.85	10%	A coffee price change
$1,500	$1,620	8%	A rent renewal
$60,000	$63,000	5%	An annual raise
2,400	3,000	25%	Monthly website visitors
50	100	100%	A value that doubled

A result above 100% simply means the new number is more than double the old one. Going from 50 to 150 is a 200% increase, because the value grew by twice its starting size.

Examples you can reopen

Coffee from $4 to $5 is a 25% increase.
The same cup back from $5 to $4 is a 20% decrease.
Add 5% to $1,850 and the new amount is $1,942.50.
Reverse a 30% increase that ended at 13 and the original is 10.

A starting value of 0 cannot produce a percent change, because you would be dividing by zero. The result is undefined. The same is true when you try to reverse a change of exactly −100%.

Questions people ask

How do you calculate a percentage increase?

Subtract the starting value from the new value, divide by the starting value, and multiply by 100. A move from 4 to 5 is (5 − 4) / 4 × 100, which is a 25% increase.

What if the number went down?

Use the same formula. A negative result is a decrease, and this calculator labels it that way. From 5 to 4 the change is −20%.

What happens when the starting value is 0?

The percentage is undefined, because the formula divides by the starting value. You will see the word undefined, not a blank result or an infinity symbol.

Can the result be more than 100%?

Yes. Doubling a number is a 100% increase. Going from 100 to 250 is a 150% increase. A 100% decrease means the new value is 0.

How do I add a percent, or undo one?

To add 5% to $1,850, multiply by 1.05, which is $1,942.50. To undo a 30% increase that landed on 13, divide 13 by 1.30, which returns 10. A change of exactly −100% has no single original value.

Do you store what I type?

No. The math runs in your browser. The numbers are not sent to a server to be calculated, and you do not need an account.