Marketing calculators
Percentage Change Calculator
Express the change from an old value to a new value as a percentage. Your inputs stay in this browser.
Live calculator
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What this calculator measures
Percentage change compares a new value with an old value and uses the absolute old value as the denominator, preserving direction for negative baselines.
Formula
% Change = ((New Value - Old Value) / |Old Value|) x 100
Inputs and variables
- Old value
- Enter the value used by this formula.
- New value
- Enter the value used by this formula.
How to use the calculator
- Choose a display currency when money fields are present.
- Enter values that cover the same period, scope, and currency.
- Review the result, formula, and worked example before using the estimate in a decision.
- Change one assumption at a time to understand what drives the result.
Worked example
- 1A value moves from 80 to 100.
- 2The increase is 20; 20 / |80| x 100 = 25%.
How to interpret the result
Positive means upward movement and negative means downward movement under this signed convention.
Common mistakes and limits
- Reversing old and new values, using zero as baseline, or confusing percentage change with percentage-point change.
Frequently asked questions
Why is old value absolute?
It keeps the denominator positive while the numerator carries direction.
Why is zero invalid?
Relative change from a zero baseline is undefined.
Are percentage points different?
Yes. Moving from 20% to 25% is five percentage points but 25% relative growth.