# Percentage Change Calculator

Calculate percentage increase or decrease between two values instantly. Free online percentage change calculator with absolute change and direction.

## What this calculates

Quickly calculate the percentage change between an old value and a new value. This tool determines whether the change is an increase or decrease, shows the absolute difference, and computes the exact percentage change.

## Inputs

- **Old Value (Original)** — The initial or starting value.
- **New Value** — The final or updated value.

## Outputs

- **Percentage Change** — The percentage increase or decrease.
- **Absolute Change** — The difference between the new and old values.
- **Direction** — formatted as text — Whether the change is an increase, decrease, or no change.

## Details

Percentage change measures how much a quantity has increased or decreased relative to its original value. The formula is: Percentage Change = ((New Value - Old Value) / |Old Value|) x 100. A positive result indicates an increase, while a negative result indicates a decrease.

This calculation is widely used in finance to track stock price movements, revenue growth, and inflation rates. In science, it measures changes in experimental results. In everyday life, it helps compare prices, weights, and other measurable quantities over time.

For example, if a product's price goes from $50 to $65, the percentage change is ((65 - 50) / 50) x 100 = 30% increase. If the price drops from $65 to $50, the change is ((50 - 65) / 65) x 100 = -23.08% decrease. Note that percentage change is not symmetric: a 30% increase followed by a 23.08% decrease returns to the original value.

## Frequently Asked Questions

**Q: What is the formula for percentage change?**

A: The formula is: Percentage Change = ((New Value - Old Value) / |Old Value|) x 100. The absolute value of the old value is used in the denominator to handle cases where the original value is negative.

**Q: Why is percentage change not symmetric?**

A: Percentage change depends on the reference value. A 50% increase from 100 gives 150, but a 50% decrease from 150 gives 75, not 100. The base value changes between the two calculations, producing different percentages for the same absolute change.

**Q: Can I calculate percentage change from zero?**

A: No. The formula requires dividing by the old value, and division by zero is undefined. If the old value is zero and the new value is non-zero, the change is technically infinite. In practice, you may need to use a different metric for such scenarios.

**Q: What is the difference between percentage change and percentage difference?**

A: Percentage change measures change from a specific original value to a new value, using the original as the denominator. Percentage difference compares two values without a clear before/after relationship, using their average as the denominator: |V1 - V2| / ((V1 + V2) / 2) x 100.

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Source: https://vastcalc.com/calculators/math/percentage-change
Category: Math
Last updated: 2026-04-21