Percentage Change Calculator
Calculate the percentage change between two values. Enter any two of three fields — starting value, ending value, or percentage change — and the third is computed automatically. The result is signed: positive for an increase, negative for a decrease.
How to Calculate Percentage Change
Formula: (Ending Value − Starting Value) / Starting Value × 100
Example — increase: A product price rises from $80 to $100.
- Change: 100 − 80 = 20
- Percentage change: 20 / 80 × 100 = +25%
- Absolute change: +20
Example — decrease: A product price falls from $100 to $80.
- Change: 80 − 100 = −20
- Percentage change: −20 / 100 × 100 = −20%
- Absolute change: −20
Reverse Calculation
Fill in any two fields and the third is computed automatically.
- Starting + Ending → Percentage Change:
(V2 − V1) / V1 × 100
- Starting + Percentage → Ending Value:
Ending = Starting × (1 + % / 100)
- Ending + Percentage → Starting Value:
Starting = Ending / (1 + % / 100)
Percentage Change vs Percentage Difference
| Percentage Change | Percentage Difference |
|---|
| Direction | Yes (signed) | No (always positive) |
| Base | Starting value | Average of both values |
| Use when | Before vs after | Two values, no clear starting point |
Example: Going from 80 to 100 is a +25% change (base = 80) but a 22.22% difference (base = average of 80 and 100 = 90).
Common Use Cases
- Tracking price changes over time (stocks, products, currencies)
- Calculating salary increases or decreases
- Measuring growth in metrics (revenue, traffic, users)
- Comparing budget vs actual spending
Frequently Asked Questions
What is percentage change?
Percentage change measures how much a value has changed relative to its starting point. The formula is: Percentage Change = (Ending Value − Starting Value) / Starting Value × 100. A positive result means an increase; a negative result means a decrease.
What is the percentage change formula?
Percentage Change = (V2 − V1) / V1 × 100, where V1 is the starting value and V2 is the ending value. For example, if a price rises from 80 to 100, the percentage change is (100 − 80) / 80 × 100 = 25%. If it falls from 100 to 80, the change is (80 − 100) / 100 × 100 = −20%.
What does a negative percentage change mean?
A negative percentage change means the value decreased. For example, −20% means the ending value is 20% lower than the starting value. This calculator automatically shows negative values for decreases — there is no need to switch modes.
Can I find the starting or ending value from a percentage change?
Yes. Enter any two of the three fields and the third is calculated automatically. To find the ending value: Ending = Starting × (1 + Percentage / 100). To find the starting value: Starting = Ending / (1 + Percentage / 100).
What is the difference between percentage change and percentage difference?
Percentage change has a direction — it uses the starting value as the base and tells you how much something grew or shrank. Percentage difference has no direction — it compares two values symmetrically using their average as the base. Use percentage change when you have a clear before-and-after, and percentage difference when comparing two values without a reference direction.