Percentage Change Calculator
Calculate the percentage increase or decrease between an old value and a new value.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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This calculator finds the percentage change between two numbers. Enter your old value and new value, and the result updates instantly as you type. No buttons needed.
- Enter the old value. This is your starting number, baseline, or original amount. It can be a price, score, measurement, or any numeric value.
- Enter the new value. This is the updated number you want to compare against the original.
- Read the result. The percentage change appears immediately, along with the absolute difference and whether it was an increase or decrease. Use Copy to grab the result or Share to send a pre-filled link.
The formula used is: ((New Value - Old Value) / |Old Value|) x 100. A positive result means an increase. A negative result means a decrease. The calculator handles decimals, negatives, and large numbers without any issues.
About Percentage Change
Percentage change measures how much a value has grown or shrunk relative to its original amount. It is one of the most common calculations in finance, business, science, and everyday life. You use it when comparing prices over time, tracking investment returns, measuring growth rates, or analyzing data trends.
The key distinction between percentage change and percentage difference is that percentage change has a direction: it measures from a specific starting point to an ending point. Percentage difference, by contrast, measures the gap between two values without assigning a direction.
Frequently Asked Questions
What is the formula for percentage change?
The formula is ((New Value - Old Value) / |Old Value|) x 100. For example, going from 80 to 100 gives ((100 - 80) / 80) x 100 = 25% increase.
What happens if the old value is zero?
Percentage change from zero is mathematically undefined because you would be dividing by zero. The calculator will not display a result in this case. If your starting value is zero, consider using absolute change instead.
What is the difference between percentage change and percentage difference?
Percentage change measures from a specific starting point (old value) to an endpoint (new value) and has a direction (increase or decrease). Percentage difference compares two values symmetrically using their average as the base, without indicating which is the starting point.