calculation

Percentage Change Calculator

Calculate the percentage change between two values. Useful for determining price increases, discounts, or growth rates.

Calculate Percentage Change

Enter the original value (a) and the new value (b) to calculate the percentage change.


Apply to a Price or Value

See how this percentage change affects a specific price or value.

Percentage Change Formula

To calculate the percentage change between two values, use the following formula:

Percentage Change = (New Value - Original Value) / Original Value × 100

Frequently Asked Questions

Find the answers to the most frequently asked questions below. If your question isn't here, or you need more info, or have feedback, please reach out.

What's the difference between percentage change and percentage points?

People mix these up all the time. Percentage change measures the relative difference between two values (like a 10% increase in sales), while percentage points measure the absolute difference between two percentages. For example, if unemployment rises from 5% to 8%, that's a 3 percentage point increase, but a 60% relative increase. Our calculator gives you the percentage change, not percentage points.

How do I calculate a discount using percentage change?

For discounts, just enter the original price as your initial value and the sale price as your final value. The calculator will show a negative percentage, indicating a reduction. For example, if something costs $50 and is on sale for $40, enter 50 and 40 to see a -20% change. You can also work backwards by entering the original price in the 'Apply to a Price' section to see how much you're saving.

What is a good calculator for stock market returns?

Tools23.com's percentage change calculator works for basic stock returns. Enter your purchase price as the initial value and current price as the final value. The percentage change shows your return (or loss). Just remember this doesn't account for dividends or splits. For more complex investment analysis you might need specialized tools, but for quick checks on price appreciation this works fine.

Why does calculating percentage increase then decrease not get me back to the original number?

This trips up a lot of people. If you increase a value by 50% and then decrease by 50%, you don't end up with the original value. That's because each percentage change is relative to the current value. For example, start with 100, increase by 50% to get 150, then decrease by 50% gives you 75, not 100. The base value for each calculation changes, which is why you need to be careful when working with sequential percentage changes.

How do I calculate the markup percentage for retail pricing?

For retail markup, you'd typically use cost as the initial value and selling price as the final value. The percentage change represents your markup percentage based on cost. So if an item costs $40 to produce and sells for $60, that's a 50% markup. Some retailers prefer to calculate margin instead (profit divided by selling price), which would be ($60-$40)/$60 = 33.3% in this example. Our calculator gives you the markup on cost.

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