Percentages are everywhere: exam marks, shop discounts, salary hikes, GST, interest rates and investment returns. This calculator handles the three most common percentage questions. Pick the question, enter two numbers and get the answer with the working shown.
How to use the percentage calculator
- Choose what you want to find.
- Enter the values for X and Y. The labels change to show what each number means.
- The answer and the calculation steps appear instantly.
The three percentage formulas
X% of Y = X × Y ÷ 100
X is what % of Y = X ÷ Y × 100
% change from X to Y = (Y − X) ÷ X × 100Examples
- 20% of 500 = 20 × 500 ÷ 100 = 100
- 75 is what % of 300? 75 ÷ 300 × 100 = 25%
- 500 to 600 = (600 − 500) ÷ 500 × 100 = 20% increase
- 500 to 400 = (400 − 500) ÷ 500 × 100 = 20% decrease
Everyday uses
| Question | Calculation | Answer |
|---|---|---|
| Marks: 450 out of 500 | 450 ÷ 500 × 100 | 90% |
| Discount: 20% off ₹2,000 | 20 × 2,000 ÷ 100 | ₹400 off, pay ₹1,600 |
| Salary hike: ₹40,000 to ₹46,000 | 6,000 ÷ 40,000 × 100 | 15% hike |
| Price with 18% GST on ₹1,000 | 1,000 × 1.18 | ₹1,180 |
For GST, the GST calculator also splits CGST and SGST.
Percent vs percentage points
If an interest rate moves from 8% to 10%, it rose by 2 percentage points, but by 25 percent (because 2 is 25% of 8). News reports and bank notices often use these differently, so it helps to know which one is meant.
FAQ
How do I calculate my marks percentage?
Divide the marks you scored by the total marks and multiply by 100. Choose "X is what % of Y", enter your marks as X and the total as Y.
How do I add a percentage to a number?
Multiply the number by (1 + percentage ÷ 100). To add 15% to ₹2,000: 2,000 × 1.15 = ₹2,300.
How do I find the original price before a discount?
Divide the sale price by (1 − discount ÷ 100). If you paid ₹1,600 after a 20% discount, the original price was 1,600 ÷ 0.8 = ₹2,000.
Why is a 50% fall not undone by a 50% rise?
Because the percentages apply to different bases. ₹100 falls 50% to ₹50, and a 50% rise on ₹50 only brings it to ₹75. To get back to ₹100 you need a 100% rise.