---
title: "Percentage Change Calculator | formformform"
description: "Calculate percentage increase, decrease and difference between two values with the formula shown."
url: "https://www.formformform.com/tools/percentage-change-calculator"
type: static
generatedAt: "2026-08-23T18:56:58.727Z"
---
# Percentage change calculator

Calculate percentage increase, decrease, difference and reverse percentages.

Calculate the percentage increase or decrease between two numbers, or reverse a percentage change. Results update as you type and stay in your browser.

## Change compared with the starting value

Percentage change is (new − old) ÷ |old| × 100. Using the starting value as the denominator makes increases and decreases comparable.

## Zero needs special treatment

A percentage change from zero is undefined, so the calculator shows the absolute difference instead.

## Frequently asked questions

Can percentage change exceed 100%?

Yes. Going from 10 to 25 is a 150% increase.

Why are opposite changes not symmetrical?

A 50% fall halves a value; returning to the original then requires a 100% increase.

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