Percentage Change Calculator

Use this calculator to estimate percentage increase or decrease between two values. Useful for analysing growth, tracking performance, and comparing changes over time.

What this calculator does

The percentage change calculator helps measure how much a value has changed relative to its original value.

It is useful for:

• growth analysis
• pricing comparisons
• business reporting
• performance tracking

How to use the percentage change calculator

1. Enter the old value (starting value)
2. Enter the new value (ending value)
3. The calculator will return the percentage change

A positive result indicates an increase, while a negative result indicates a decrease.

Percentage change formula

Percentage Change = ((New Value - Old Value) / Old Value) x 100

Where:

• Old Value = starting number
• New Value = ending number
• Percentage Change = increase or decrease as a percentage

Example calculation

If a value changes from 100 to 120:

• Percentage change = ((120 - 100) / 100) x 100
• Percentage change = 20%

This means the value increased by 20%.

If the value changed from 100 to 80:

• Percentage change = ((80 - 100) / 100) x 100
• Percentage change = -20%

This means the value decreased by 20%.

What is percentage change?

Percentage change measures the relative increase or decrease between two values.

It shows how much something has changed compared to where it started.

Why percentage change matters

Percentage change helps you:

• track growth over time
• compare performance between periods
• measure price movements
• evaluate trends and progress
• support data-driven decisions

Percentage change vs percentage

These are different concepts.

• Percentage -> shows a portion of a whole
• Percentage change -> shows how much a value increased or decreased

Use a standard percentage calculator when working with proportions.

When to use this calculator

Use this calculator when you need to:

• compare sales or revenue between periods
• track pricing changes
• measure improvement or decline
• evaluate business or marketing performance
• analyse financial or operational data

Common mistakes when calculating percentage change

Common mistakes include:

• using the wrong starting value (old value must be the base)
• confusing percentage change with total percentage
• ignoring negative results (declines)
• dividing by the new value instead of the old value

Always use the original value as the denominator.

Related calculations

You may also want to:

• Use the Percentage Calculator
• Use the Revenue Growth Calculator
• Use the Profit Margin Calculator
• Use the Break Even Calculator

Useful resources

• Google Sheets - calculate percentage change with formulas
• Excel - built-in growth and comparison formulas
• Financial reports - track performance trends over time

FAQs

What is percentage change?

Percentage change measures how much a value increased or decreased relative to the original value.

How do you calculate percentage change?

Percentage Change = ((New Value - Old Value) / Old Value) x 100.

Why is percentage change important?

It helps compare performance, trends, and changes over time.

Can percentage change be negative?

Yes. A negative result means the value decreased.

Interpreting your result

Your percentage change result should always be interpreted in context:

• compare it against the absolute change as well as the percentage
• review the starting value so small bases do not mislead decisions
• compare comparable periods to reduce seasonality effects
• separate one-off changes from recurring trend shifts

A large percentage change from a small base can look more important than it really is.

Data quality checklist

Before acting on this result, verify:

• old and new values are measured on the same basis
• the periods compared are truly comparable
• returns, discounts, and anomalies are handled consistently
• the original value is not zero

Small inconsistencies can create misleading percentage changes.

How to improve this metric

Practical ways to improve a percentage change metric depend on the underlying business driver, but often include:

• focus on the main lever behind the change
• segment the analysis by product, channel, or period
• compare both relative and absolute movement
• avoid reacting to noise from one-off spikes

Improvement is most reliable when percentage change is tied back to the underlying commercial driver.

Benchmarks and target setting

A good target depends on the metric being measured.

When setting targets:

• compare against your trailing trend before using external benchmarks
• define both acceptable and aspirational ranges
• pair change targets with absolute value thresholds
• review targets when demand or market conditions shift

Your own historical trend is usually the most useful reference point.

Reporting cadence and decision workflow

For most teams, a simple cadence works best:

• Weekly: monitor fast-moving changes during active campaigns or trading periods
• Monthly: compare against plan and prior periods
• Quarterly: reassess the trend and target range

A practical workflow is to calculate the change, validate the base numbers, identify the main driver, test one action, and then review the next period before scaling.

Common analysis scenarios

You can use this calculation in several practical scenarios:

• month-over-month KPI reporting
• year-over-year business performance analysis
• pricing and revenue reviews
• board and management reporting

In each scenario, pair the percentage change with absolute movement so the size of the change is clear.

FAQ extensions

Can percentage change be more than 100%?

Yes. If the new value is more than double the original value, the percentage change will exceed 100%.

What if the original value is zero?

Standard percentage change cannot be calculated because division by zero is undefined.

Is percentage change the same as percentage points?

No. Percentage change measures relative movement, while percentage points measure the arithmetic difference between two percentages.