Everyday formula
Percentage Change Formula
Understand the percentage increase and decrease formula from an original value to a new value.
Formula
Percentage change = ((new value − original value) ÷ |original value|) × 100What the formula means.
Find the difference between the new and original values, divide by the magnitude of the original value, then convert the ratio to a percentage.
The original value is the denominator.
A negative result means a decrease.
A move from 50% to 60% is a 10 percentage-point increase but a 20% relative increase.
Variables.
OOriginal value
The starting value used as the comparison base.
NNew value
The value after the change.
Δ%Percentage change
The change relative to the original value.
Worked example.
From 80 to 100
- 100 − 80 = 20
- 20 ÷ 80 = 0.25
- 0.25 × 100 = 25%
Try your own numbersPercentage Change Calculator
↗Common mistakes.
- Dividing by the new value instead of the original value.
- Ignoring the sign of the change.
- Using the formula when the original value is zero.
Quick questions.
Why is the original value the denominator?
Percentage change measures the size of the change relative to where the value started.
Can percentage change be more than 100%?
Yes. If the increase is larger than the original value, the percentage increase exceeds 100%.