Percentage Decrease Calculator
Decrease % = (Original − New) ÷ Original × 100(100 − 80) ÷ 100 × 100 = 20%
Free online tool
Percentage Decrease Calculator
Measure how much a value fell relative to its original amount.
Instant calculation
Calculate percentage decrease
Compare a smaller new value with the original value.
Your result
Calculation
Your numbers stay in this browser. Nothing is uploaded or saved.
Three clear steps
How to use this calculator
- 01
Enter the original
Type the value before the decrease.
- 02
Enter the new value
Type the smaller value after the decrease.
- 03
Calculate the decrease
See the percentage decrease and absolute change.
The formula
How this calculation works
Subtract the new value from the original value, divide by the original value and multiply by 100.
Check the method
Worked examples
Each example follows the same formula used by the calculator.
What is the decrease from 100 to 80?
(100 − 80) ÷ 100 × 100 = 20%20% decreaseWhat is the decrease from 250 to 200?
(250 − 200) ÷ 250 × 100 = 20%20% decreaseCommon questions
Questions about this calculation
What is the percentage decrease formula?
Subtract the new value from the original value, divide by the original value, and multiply by 100.
What is the percentage decrease from 100 to 80?
The decrease is 20% because the difference of 20 divided by the original 100 equals 0.20.
Why must the original value be positive?
This standard percentage decrease formula measures the fall from a positive starting baseline. For changes involving a negative baseline, use the Percentage Change Calculator.
Can a percentage decrease be more than 100%?
For ordinary non-negative quantities, a fall to zero is a 100% decrease. Results beyond that usually involve a negative new value and need context.
What if the new value is larger?
Use the Percentage Increase Calculator or Percentage Change Calculator when the new value is larger than the original.
Continue calculating