Percentage Change Calculator
Percentage change is the change divided by the starting value: going from 80 to 100 is +25 %.
25 %
- Absolute change
- 20
- New value as % of old
- 125 %
- Direction
- Increase
Step-by-step solution
- Percentage change = (New − Old) ÷ |Old| × 100 %
- = (100 − 80) ÷ 80 × 100 % = 25 %
Percentage Change Formula
% change = (New − Old) ÷ |Old| × 100 %
Old: starting value, New: ending value
Worked Example
A value rising from 80 to 100:
- Percentage change = (New − Old) ÷ |Old| × 100 %
- = (100 − 80) ÷ 80 × 100 % = 25 %
New value as % of old: 125 % · Direction: Increase
Percentage change versus percentage points
Percentage change compares the new value with the old one: (new − old) ÷ old × 100. A rise from 4 % to 5 % is a change of 1 percentage point but a 25 % increase. Changes are not symmetric: a 20 % fall followed by a 20 % rise leaves you 4 % below where you started, because the second change is taken on a smaller base. When the old value is zero the percentage change is undefined.
Frequently asked questions
Why is 80 → 100 a 25 % increase but 100 → 80 a 20 % decrease?
The change (20) is divided by the starting value, which is different in each direction: 20 ÷ 80 = 25 % but 20 ÷ 100 = 20 %.
What is the difference between percentage change and percentage points?
If an interest rate rises from 4 % to 5 %, it rose by 1 percentage point but by 25 % in relative terms.
How do I calculate growth over several years?
For an average yearly rate use CAGR = (End ÷ Begin)^(1/n) − 1 rather than dividing the total percentage change by the number of years.
Sources
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Percentage Change Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/percentage-change-calculator/
IEEE
Scientific Converters, "Percentage Change Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/percentage-change-calculator/