Percentage Calculator

Calculate percentages in every way you need.

Free & unlimited

Mode

Find a percentage of a number

Percentage (%)

Of value

Result

All processing happens in your browser. No data is sent to any server.

About this tool

1
Choose a calculation mode
Select from "X% of Y", "X is what % of Y", or "percentage increase/decrease between two values".
2
Enter your numbers
Fill in the known values - the tool calculates the missing one instantly.
3
View the result
See the answer with the formula shown so you understand the math behind it.

To find a percentage increase, the formula is ((new - old) / old) x 100.
A 50% decrease followed by a 50% increase does NOT return to the original - it gives you 75% of the start.
When calculating discounts, "30% off $80" is the same as 0.70 x $80 = $56.
Reverse percentage: if a price after 20% tax is $120, the pre-tax price is $120 / 1.20 = $100.

Three calculation modes: of, is-what-%, and change
Step-by-step formula display
Instant calculation as you type
Percentage increase and decrease calculator
Reverse percentage (find original value before % change)

Calculate sale prices and discounts while shopping.
Determine percentage growth or decline in business metrics.
Figure out exam scores and grade percentages.
Compute tax amounts and tip percentages.

Because the 50% gain is calculated on the reduced amount. If you start with $100, lose 50% ($50 left), then gain 50% of $50 ($25), you end at $75 - not $100.

Divide the sale price by (1 - discount rate). For example, if an item costs $60 after a 25% discount: $60 / 0.75 = $80 original price.

A change from 10% to 15% is a 5 percentage point increase, but a 50 percent increase. Percentage points measure the absolute difference; percent measures relative change.