Why can't I start from zero?

Percentage change from zero is undefined (you can't express a change as a share of nothing), so the calculator shows 0 in that case.

Percentage Change Calculator

Find the percentage increase or decrease between two numbers.

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Change % = (New − Old) ÷ Old × 100

A positive result is an increase; a negative result is a decrease.

Going from 100 to 125 is a 25% increase. Going from 200 to 150 is a 25% decrease.

Why can't I start from zero?: Percentage change from zero is undefined (you can't express a change as a share of nothing), so the calculator shows 0 in that case.