Percentage Change Calculator
Enter an initial and a final value to get the percentage change between them — the calculator tells you whether it is an increase or a decrease and shows the working.
Reviewed by the OmniCalc teamMethod verified 2026-07-01
25%
Percentage change 25% — increaseShow steps
- Find the absolute change: V₂ − V₁ = 100 − 80 = 20.
- Divide by the magnitude of the initial value: 20 ÷ |80| = 0.25.
- Multiply by 100: 0.25 × 100 = 25%.
- That is a 25% increase.
How to use the percentage change calculator
- 1Enter the initial value (V₁) — the number you are starting from.
- 2Enter the final value (V₂) — the number you ended up with.
- 3Read the percentage change: positive means an increase, negative means a decrease.
- 4Open Show steps under the result to see the exact arithmetic.
The formula
% change = (V₂ − V₁) ÷ |V₁| × 100
The difference is divided by the magnitude of the initial value, so the sign of the result reflects the direction of the change — positive is an increase, negative is a decrease. Every answer comes with a “Show steps” breakdown so you can follow the exact arithmetic.
A change doesn't reverse symmetrically
A +50% increase followed by a −50% decrease does notbring you back to the start: 100 → 150 → 75. Each change is measured from a different initial value, so change percentages don’t add up.
Frequently asked questions
How is percentage change calculated?
Percentage change is the difference between the two values divided by the magnitude of the initial value, times 100: (V₂ − V₁) ÷ |V₁| × 100. A positive result is an increase and a negative result is a decrease.
What is the difference between percentage change and percentage difference?
Percentage change has a direction — it measures a move from a starting value to an ending one, so order matters and the result can be positive or negative. Percentage difference compares two values symmetrically against their average and is always reported as a positive figure.
Why can't I start from zero?
The formula divides by the initial value, so if V₁ is 0 the calculation is a division by zero and percentage change is undefined. There is no meaningful percentage between nothing and something — you would need a different measure such as the absolute change.