Percentage Change Calculator – Increase or Decrease
Calculate percentage increase or decrease between an old and new non-negative value with correct zero-baseline validation.
Measure relative change using the old value as the baseline.
How it works
Percentage Change = (New − Old) ÷ Old × 100.
Example
A move from 100 to 120 is +20%; a move from 100 to 80 is −20%.
Frequently asked questions
What happens when the old value is zero?
Percentage change from a zero baseline is undefined, so the calculator reports a validation message instead of Infinity.
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