Percentage increase
A positive result means the new value is higher than the original value.
Percentage change—
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Calculate percentage change
Enter an old value and a new value to calculate the percentage change. The result shows whether the value increased or decreased and measures that change relative to the original value.
Percentage decrease
A negative result means the new value is lower than the original value.
Original value matters
Percentage change is measured relative to the starting value, not simply the difference between the two numbers.
Percentage change worked example
If a value rises from 80 to 100, the difference is 20. Divide 20 by the original value of 80 and multiply by 100: (100 − 80) ÷ 80 × 100 = 25%. The percentage change is therefore a 25% increase.
A starting value of zero does not have a conventional percentage-change result.
How percentage change is calculated
Percentage change measures the difference between the old and new values relative to the old value: (new − old) ÷ old × 100. A positive result is an increase and a negative result is a decrease. If the starting value is zero, an ordinary percentage-change result is not defined.
Frequently asked questions
What is the percentage change formula?
Percentage change = (new value − original value) ÷ original value × 100.
Can percentage change be over 100%?
Yes. If the increase is larger than the original value, the percentage increase can exceed 100%.
Why can a decrease not go below −100%?
A value cannot fall by more than its entire original amount unless it becomes negative.
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