Percentage Decrease Calculator
Reduce a number by a percentage, or find the percentage decrease between two numbers.
Enter your values to see the result.
Everything is calculated entirely in your browser. Nothing is sent to a server.
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How to use this tool
- 1Pick “Decrease a number by a percentage” or “Percentage decrease between two numbers”.
- 2Enter the values — a number and a percentage, or the starting and new values.
- 3Read the result and the amount of change.
Features
- Two calculations in one: subtract a percent from a number, or find the % decrease between two numbers.
- Warns you when the change is actually an increase.
- Explains the zero-start case instead of showing a misleading answer.
- Results shown to up to four decimal places.
- No account or sign-up required.
Privacy
All calculations happen in your browser. Nothing is sent to a server.
Frequently asked questions
How do I calculate a percentage decrease?
Subtract the new value from the old value, divide by the old value, and multiply by 100. Going from 80 to 60 is (80 − 60) ÷ 80 × 100 = 25% decrease.
How do I reduce a number by a percentage?
Multiply the number by (1 − percent ÷ 100). Reducing 200 by 15% gives 200 × 0.85 = 170.
What’s the difference between percentage decrease and percentage points?
A drop from 10% to 8% is 2 percentage points, but a 20% decrease in the rate itself. Percent change compares the two values relative to the starting one.
Can a percentage decrease be more than 100%?
Not for a value that can’t go below zero — a 100% decrease takes you to zero. A larger “decrease” would mean the value became negative.