Percentage Change Formula
Formula
Change % = (new − old) ÷ old × 100
Variables
- old
- Starting value (must not be zero)
- new
- Ending value
Worked example
From 80 to 100: (100 − 80) ÷ 80 × 100 = 25%.
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Frequently asked questions
What if the old value is zero?
Percentage change is undefined when the starting value is zero.