How to use: Percentage calculator
- 1To find a percentage of a number, use "What is X% of Y?", for example 18% of 2500.
- 2To find your percentage marks, use "X is what % of Y?", for example 425 of 500.
- 3To find a rise or fall, use "Percentage change" with the old and new values.
- 4Read the answer under each calculator. Negative changes are shown in red.
Formulas
- X% of Y = X ÷ 100 × Y
- X as a percentage of Y = X ÷ Y × 100
- Percentage change = (New − Old) ÷ Old × 100
Everyday examples
| Question | Answer |
|---|---|
| 18% GST on ₹2,500 | ₹450 |
| 425 marks out of 500 | 85% |
| Price up from ₹200 to ₹250 | +25% |
| Weight down from 80 kg to 72 kg | −10% |
CGPA to percentage
Many Indian universities convert CGPA to a percentage by multiplying by 9.5 (the CBSE method), so a CGPA of 8.2 is about 77.9%. Check your university’s official rule, as some use different formulas.
Frequently asked questions
How do I calculate percentage of marks?
Divide the marks you scored by the total marks and multiply by 100. For 425 out of 500, 425 ÷ 500 × 100 = 85%.
How do I calculate percentage increase?
Subtract the old value from the new one, divide by the old value and multiply by 100. A salary rise from ₹40,000 to ₹46,000 is (46,000 − 40,000) ÷ 40,000 × 100 = 15%.
How do I work out a discount?
Use "What is X% of Y?" with the discount rate and price to get the discount amount, then subtract it from the price. 30% off ₹1,200 is ₹360 off, so you pay ₹840.
Why is a 50% fall followed by a 50% rise not back to the start?
Percentages are calculated on different bases. ₹100 down 50% is ₹50, and ₹50 up 50% is only ₹75.