Percentage decrease calculator
Find the percent drop from an old value to a new value.
How the percentage decrease calculator works
Enter the original value and the new, lower value, then press “Calculate decrease”. A price falling from 250 to 200 is a 20% decrease. The tool also shows the absolute drop alongside the percent.
decrease % = ((old − new) ÷ old) × 100
If the new value is higher than the old one, that’s growth — see the percentage increase calculator for that case.
Percentage decrease calculator FAQ
What is the percentage decrease formula?
Subtract the new value from the old value, divide by the old value, and multiply by 100: ((old − new) ÷ old) × 100.
Why can’t the original value be zero?
Division by zero is undefined — a percent change from zero has no meaningful answer, so the tool asks for a non-zero original value.
Can a decrease be more than 100%?
Mathematically yes, if the new value goes negative (100 down to −50 is a 150% decrease). For prices and everyday quantities, which can’t go below zero, decreases top out at 100%.
What does a negative result mean?
The new value is higher than the old one — that is an increase, not a decrease. The page points you to the percentage increase calculator.