How to Use This Calculator
- Select your question: Choose whether you need to find a fraction of a number, determine a ratio, or compute change.
- Enter your numbers: Fill in the values. Results update instantly as you type.
- Observe the formulas: View the exact arithmetic operation step-by-step.
Formula and Calculation Steps
Percentage of Number: Result = (P / 100) × Y
What Percentage: Result = (X / Y) × 100
Percentage Change: Result = ((New - Old) / |Old|) × 100Worked Examples and Reference Table
| Percentage | Of $50 | Of $100 | Of $250 | Of $500 |
|---|---|---|---|---|
| 5% | $2.50 | $5.00 | $12.50 | $25.00 |
| 10% | $5.00 | $10.00 | $25.00 | $50.00 |
| 15% | $7.50 | $15.00 | $37.50 | $75.00 |
| 20% | $10.00 | $20.00 | $50.00 | $100.00 |
| 25% | $12.50 | $25.00 | $62.50 | $125.00 |
| 50% | $25.00 | $50.00 | $125.00 | $250.00 |
Frequently Asked Questions
How do you calculate a percentage of a number?
Convert the percentage into a decimal by dividing by 100, then multiply by the total number. For example, 20% of 150 is 0.20 * 150 = 30.
How do you calculate percentage increase or decrease?
Subtract the old value from the new value, divide by the absolute old value, and multiply by 100: ((New - Old) / Old) * 100.
What is the difference between percentage and percentage points?
A percentage represents a relative ratio, while percentage points measure the simple arithmetic difference between two percentages (e.g. going from 10% to 15% is a 5 percentage point increase, but a 50% relative increase).
Can a percentage be greater than 100%?
Yes. Any quantity that exceeds the base or comparison value results in a percentage over 100%. For instance, 250 is 250% of 100.
How do you find the original price before a percentage discount?
Divide the discounted sale price by (1 - discount percentage / 100). If an item costs $80 after a 20% discount, the original was $80 / 0.80 = $100.