Percentage Decrease Calculator
Calculate the percentage decrease between two numbers or apply a percent drop to a value with this free maths calculator in your browser.
Enter Values
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How to use this calculator
- Enter the value and the decrease.
- Press Calculate.
How it works
Subtracts a percentage from a value: result = value × (1 − percent ÷ 100).
Worked example
200 − 25%. = 150.
Common mistakes
- Subtracting the percentage from the new value instead of the original.
- Forgetting that a decrease then an equal increase doesn't return to the start.
Frequently asked questions
How do I calculate a percentage decrease?
Decrease = (old − new) ÷ old × 100. To take x% off a number, multiply it by (1 − x ÷ 100).
Why doesn't a 20% drop then 20% rise return to the start?
The rise applies to the smaller amount, so you end up below the original — each percentage is taken from a different base.
Does a 25% decrease then a 25% increase return to the start?
No — each percentage applies to a different base. 200 −25% = 150, then +25% = 187.5, not 200.
Related tools
- Percentage Increase Calculator
- Discount Calculator
- Percent Error Calculator
- Percentage Difference Calculator
- Reverse Percentage Calculator
- Fraction to Percent Calculator
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Cite this tool
Zerdly. (2026). Percentage Decrease Calculator. Retrieved from https://www.zerdly.com/tools/percentage-decrease-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.