Percent Change Calculator
Percentage increase or decrease between two numbers. Change the numbers and the result updates instantly.
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How it works
Percent change = (new value - old value) / old value x 100. A positive result is an increase and a negative result is a decrease. The change is always measured against the starting value, so going from 80 to 100 is +25%, while going from 100 back to 80 is -20%.
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Example
Use it for prices, wages, rent, investments or any before-and-after comparison.
Tips
- Change one input at a time to see what moves the result most.
- Use realistic rates. Check current averages before you decide.
- Results are estimates and do not replace advice from a licensed professional.
Frequently asked questions
Is this calculator free?
Yes. There is no sign-up and nothing is stored on our servers; the math runs in your browser.
How accurate is it?
It uses standard formulas, but real offers include fees, rate changes and taxes that can differ. Treat the result as an estimate.
Sources and method
Page last updated November 2026. See our editorial policy and disclaimer.