Frequently Asked Questions

Percentage change = ((New Value - Old Value) / |Old Value|) × 100. A positive result is an increase; a negative result is a decrease.
((75 - 50) / 50) × 100 = 50%. This is a 50% increase.
Yes. A negative percentage change indicates a decrease. For example, going from 100 to 80 is a -20% change.
Percentage change from zero is undefined (division by zero). If the old value is 0 and the new value is not 0, the change is mathematically infinite.
Percentage change has a direction (from old to new), while percentage difference is typically the absolute difference divided by the average of both values.

Tip

Percentage change always divides by the original (old) value. Order matters — from 50 to 100 is +100%, but from 100 to 50 is -50%.