How to use this calculator
Enter two values in the same units to calculate the absolute difference and the percentage increase or decrease relative to the original.
The formula
Subtract the original value from the new one, divide by the absolute value of the original, then multiply by 100. For example, moving from 80 to 100 is a 25% increase.
Why the order matters
Moving from 100 down to 80 is a 20% decrease, not a 25% decrease. The denominator is always the original value.
When the original is zero
Percentage change from an original value of zero is undefined. Negative original values are supported using the absolute baseline, so moving from −50 to −25 is a 50% increase.
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