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Percentage Change Calculator
Your values
Enter the starting value first, then the value it changed to. A rise gives a positive change; a fall gives a negative one.
Example: a price that rises from $50 to $75 is a 50% increase — the change is +$25.
Behind the numbers
How percentage change is calculated
Percentage change compares the difference between two values to the starting value. Subtract the old value from the new value, divide by the old value, then multiply by 100. A positive answer means an increase, a negative answer means a decrease, and zero means no change.
From 50 to 75: ((75 − 50) ÷ 50) × 100 = +50%
If the old value is 0, the percentage change is undefined — you cannot divide by zero. In that case, report the absolute change instead: from 0 to 25 is a change of +25.
A few comparisons
Worked examples
| Old value | New value | Change | Difference | Verdict |
|---|---|---|---|---|
| 50 | 75 | +50% | +25 | Increase |
| 80 | 60 | −25% | −20 | Decrease |
| 100 | 100 | 0% | 0 | No change |
| 40 | 50 | +25% | +10 | Increase |
| 200 | 150 | −25% | −50 | Decrease |
Small changes. Clear answers.
Always divide by the old (starting) value, not the new one. Dividing by the new value is the most common percentage-change mistake.
A 100% increase means the value doubled; a 50% decrease means it halved. A change of more than 100% means the value more than doubled.
A change from 0 cannot be expressed as a percentage. Report the absolute change instead: from 0 to 25 is a change of +25.
Compare changes over the same period. A 10% monthly rise is not the same as a 10% yearly rise.
Good to know
Your percentage-change questions, answered.
How is percentage change calculated?
Subtract the old value from the new value, divide by the old value, and multiply by 100. For example, from 50 to 75: ((75 − 50) ÷ 50) × 100 = +50%.
What does a negative percentage change mean?
A negative percentage change means a decrease. From 80 to 60 is a −25% change, a drop of 20.
Why is percentage change undefined when the old value is 0?
Percentage change divides by the old value, and division by zero has no answer. When the old value is 0, report the absolute change instead — for example, from 0 to 25 is a change of +25.
What is the difference between percentage change and percentage points?
Percentage change is relative to the starting value, while percentage points are the plain difference between two percents. Going from 20% to 25% is a 5 percentage-point rise, but a 25% increase.