Percentage Change Calculator
Percentage change calculator: percent increase or decrease between two values, or the new value after a change.
Δ% = Vnew − VoldVold
How to use this calculator
- Choose the quantity you want under “Solve for”.
- Type the known values and pick their units: any combination works.
- The result updates as you type. Open “Show the steps” to see the substitution.
Percentage change = (new − old) ÷ old × 100. A positive result is an increase, a negative one a decrease.
It is not symmetric: going from 80 to 100 is +25 %, but from 100 back to 80 is −20 %.
Formula
Δ% = Vnew − VoldVold
| Symbol | Quantity | Units |
|---|---|---|
| Vold | Old value | — |
| Vnew | New value | — |
| Δ% | Percentage change | %, × |
Worked example
Given: Vold = 80 · Vnew = 100
Δ% = Vnew − VoldVold
Result: Δ% = 25 %
Frequently asked questions
What is the percent increase from 80 to 100?
(100 − 80) ÷ 80 = 25 %.
What is the difference between percentage change and percentage points?
From 4 % to 5 % is a 1 percentage-point rise but a 25 % relative increase.