Percentage change is always measured against the starting value, which is why going from 50 to 100 is a 100% increase while dropping back from 100 to 50 is only a 50% decrease. The tool highlights that asymmetry so the direction is never ambiguous.
Calculator
Formula used
Percent change = (new − old) ÷ old × 100 · New value = base × (1 ± percent ÷ 100)
How to use the Percentage Increase Calculator
- Enter the starting and ending values for a change calculation.
- Read the percentage change and whether it is up or down.
- Or enter a base value and a percentage to apply.
- Check the step-by-step table to see the working.
About this tool
The Percentage Increase Calculator is built for speed and accuracy: every calculation runs in your browser, so your data never leaves your device and the result updates as you type. It works equally well on a phone, a tablet or a desktop, and it is free to use as many times as you like.
Common use cases
- Measuring price inflation between two years.
- Calculating a salary raise percentage.
- Applying a discount or mark-up to a price.
- Tracking growth or decline in website traffic.
Tips for the best result
- Use the latest figures you have - even a small change in rate or term can shift the outcome by hundreds.
- For annual figures, divide by 12 to get a monthly number you can compare with the result.
- Bookmark this page and revisit the calculation as the inputs change.
Frequently asked questions
Why is my increase and decrease not symmetrical?
Because the base changes. A 50% rise from 100 gives 150, and falling back to 100 is a 33% decrease, not 50%.
How do I enter a decrease?
Type a negative percentage in the "change" field, for example -15, and the applied result will be lower than the base.
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