What Is This Tool?
The Percentage Calculator handles three common questions: A% of B, A is what percent of B, and percentage change from A to B.
What Can You Do With It?
Work out discounts and tips. Find what share one number is of another. Measure growth or decline between two values.
How Does It Work?
A% of B = A × B ÷ 100. A as a percent of B = A ÷ B × 100. Change from A to B = (B − A) ÷ A × 100.
Key Benefits
Three calculators in one. Clear errors for divide-by-zero cases.
Limitations and Important Notes
Change from 0 and share of 0 cannot be calculated. Results are shown with limited decimals.
Privacy and Security
This tool runs entirely in your web browser. Your input and results are processed on your device and are not uploaded to Usekit servers.
Real-World Example
20% of 150 = 30. 30 is what percent of 150 = 20%. Change from 80 to 100 = 25%.
Frequently Asked Questions
How do I calculate a 15% discount?
Use “A percent of B” with A = 15 and B = the price, then subtract the result from the price.
Why is a drop from 100 to 80 −20% but a rise back is 25%?
Percentage change is measured from the starting value, which is different each time.
Can results be negative?
Yes, a negative change means a decrease.
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How to use this tool
- Choose the type of calculation.
- Enter values A and B.
- Calculate and read the result.