How is percentage change calculated?

It's ((new value − old value) / old value) × 100. A positive result is an increase, a negative result is a decrease.

What if the starting value is zero?

Percentage change is undefined when the starting value is zero, since you'd be dividing by zero.

Is this different from the percentage calculator?

It's the same 'increase/decrease' mode, just as its own dedicated page for quicker access.

Percentage Increase/Decrease Calculator

Find the percentage change between two numbers.

This tool runs entirely in your browser. Your files are never uploaded to a server.

FromTo

20%

What this calculator does

Calculates the percentage change from a starting value to an ending value. A positive result means an increase and a negative result means a decrease.

How to use it

Enter the starting value and the ending value. The percentage change updates immediately and is shown to two decimal places.

Worked example

Going from 50 to 60 gives ((60 − 50) / 50) × 100 = 20%. Going from 50 to 40 gives ((40 − 50) / 50) × 100 = -20%, a decrease.

Formula

Percentage change equals (ending value − starting value) divided by the starting value, multiplied by 100.

Input behavior

The starting value must be nonzero, since dividing by zero has no defined result. Negative values are accepted, so a change that crosses zero or starts from a negative baseline needs careful interpretation.

Limitations

This is relative percentage change, not a percentage-point difference, compound growth rate, annualized rate, or a test of statistical significance.

Privacy

The calculation runs locally in your browser; the values you enter are not uploaded.

Frequently Asked Questions

How is percentage change calculated?: It's ((new value − old value) / old value) × 100. A positive result is an increase, a negative result is a decrease.
What if the starting value is zero?: Percentage change is undefined when the starting value is zero, since you'd be dividing by zero.
Is this different from the percentage calculator?: It's the same 'increase/decrease' mode, just as its own dedicated page for quicker access.

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