How to use the Percentage Calculator
- Pick the type of percentage question.
- Enter the two numbers. The labels change to match the mode.
- The answer and the working appear instantly.
Formula used
Worked examples
| Question | Working | Answer |
|---|---|---|
| What is 15% of 2,000? | 2,000 × 0.15 | 300 |
| 45 is what % of 60? | 45 ÷ 60 × 100 | 75% |
| Rent went from 25,000 to 30,000 | (30,000 − 25,000) ÷ 25,000 × 100 | 20% increase |
| Add 18% to 5,000 | 5,000 × 1.18 | 5,900 |
| Price is 1,180 after 18% was added | 1,180 ÷ 1.18 | 1,000 |
Quick mental tricks
- 10%: move the decimal one place left. 10% of 4,500 is 450.
- 5%: half of 10%. 5% of 4,500 is 225.
- Swap trick: X% of Y equals Y% of X. 8% of 50 is the same as 50% of 8, which is 4.
- Percentage points vs percent: a rate going from 10% to 12% rose by 2 percentage points, which is a 20% increase.
Working out exam results? The Marks Percentage Calculator adds grades. For shopping, try the Discount Calculator.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage, then divide by 100. For 20% of 750: 750 × 20 ÷ 100 = 150.
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100. From 200 to 250 is (250 − 200) ÷ 200 × 100 = 25%.
How do I find the original price before a percentage was added?
Divide by 1 plus the percentage as a decimal. If £120 includes 20% VAT, the original is 120 ÷ 1.2 = £100.
Why is a 50% drop followed by a 50% rise not back to the start?
Because the second percentage applies to a smaller number. 100 falls 50% to 50, and 50 rises 50% to only 75.
How do I calculate percentage in Excel?
Use =A1/B1 and format the cell as a percentage, or =A1/B1*100 for a plain number.
Our team builds and tests every tool by hand, checks each formula against official sources (IRS, HMRC, the Income Tax Department of India, CBSE, NHS, WHO) and reviews pages whenever rules change. Last reviewed on . Spotted a mistake? Tell us.