Percentage Decrease Calculator
Find the percentage decrease between two numbers.
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Calculate a percentage decrease
Enter the original value and the new value above to find the percentage decrease between them, along with the amount of the change. The decrease is the drop divided by the original amount, expressed as a percent. It is handy for price cuts, discounts, and measuring any fall from one figure to another. The calculation runs entirely in your browser.
The formula
Percentage decrease equals the original value minus the new value, divided by the original value, multiplied by 100.
How percentage decrease is calculated
The result compares the amount lost with the magnitude of the original value and shows the absolute numerical difference separately.
Method
Subtract the new value from the original value, divide by the absolute original value, and multiply by 100.
percentage decrease = (original - new) / abs(original) x 100
Worked example
From 80 down to 60, the difference is 20. Dividing 20 by 80 gives a 25% decrease.
Limits
- An original value of zero has no defined percentage decrease, so the tool does not return a result.
- If the new value is larger, the displayed decrease is negative, signaling movement in the opposite direction.
- Negative starting values can make the everyday meaning of decrease ambiguous.
Reviewed against the current calculator or processor on September 6, 2026.
Frequently asked questions
How do you calculate percentage decrease?
Subtract the new value from the original value, divide by the original value, then multiply by 100 to get the percent decrease.
What does a negative result mean?
A negative decrease means the value went up instead of down, so it is actually an increase.