Percentage Calculator
Five percentage calculators on one page, each showing the formula with your numbers in it: a percentage of a number, what percent one number is of another, percentage increase or decrease, adding or removing a percentage such as 18% GST or a discount, and marks percentage from marks obtained and total marks.
How to use Percentage Calculator
- Find the card for your question, such as "What is __ % of __?" or Marks percentage.
- Type your numbers into its boxes. Commas are fine, so 1,18,000 and 118,000 both work.
- Read the answer and the formula under it. Use the copy icon to copy the answer.
- For GST or a discount, choose Add %, Subtract % or Remove included %, then enter the amount and the rate.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. 18% of 2,500 is 2,500 × 18 ÷ 100 = 450. The first card does this; percentages over 100 and decimals such as 12.5% work too.
How do I add 18% GST to a price?
Choose Add % and enter the price and 18. The total is the price × (1 + 18 ÷ 100), so ₹1,000 plus 18% GST is ₹1,180, and the card also shows the GST itself, ₹180. For a sale within one state that GST is split equally into CGST and SGST (9% + 9% at an 18% rate); for a sale between states it is charged as IGST. Check the rate for your goods or service with the GST notifications or your accountant.
How do I remove GST from a price that includes it?
Choose Remove included % and enter the price and the rate. The price before tax is the price × 100 ÷ (100 + rate), so ₹1,180 including 18% GST is ₹1,000 before tax, and the GST in it is ₹180. Taking 18% off ₹1,180 instead would give ₹967.60, which is wrong, because the 18% was worked out on the lower price.
How do I calculate my marks percentage?
Divide the marks obtained by the total marks and multiply by 100. 456 out of 500 is 456 ÷ 500 × 100 = 91.2%. Boards and universities that grade in CGPA have their own rule for turning CGPA into a percentage, so use the formula in your marksheet or your university's notice for that.
How is percentage increase or decrease worked out?
Subtract the old value from the new one, divide by the old value and multiply by 100. A salary that goes from ₹40,000 to ₹46,000 rises by 6,000 ÷ 40,000 × 100 = 15%. Going back from ₹46,000 to ₹40,000 is a 13.04% decrease, because the starting value is different. A change from 0 has no percentage, so the card leaves it blank.
Why is a 20% rise followed by a 20% fall not back to the start?
Because each percentage is taken of a different number. 100 plus 20% is 120, and 120 less 20% is 96. To undo a percentage that was added, use Remove included % rather than Subtract %.
Percentage formulas
| Question | Formula | Example |
|---|---|---|
| What is X% of Y? | Y × X ÷ 100 | 18% of 2,500 = 450 |
| X is what % of Y? | X ÷ Y × 100 | 45 of 60 = 75% |
| % change from A to B | (B − A) ÷ A × 100 | 40,000 → 46,000 = 15% increase |
| Add P% | Amount × (1 + P ÷ 100) | 1,000 + 18% = 1,180 |
| Subtract P% (discount) | Amount × (1 − P ÷ 100) | 2,500 − 20% = 2,000 |
| Remove an included P% | Amount × 100 ÷ (100 + P) | 1,180 including 18% = 1,000 |
| Marks percentage | Obtained ÷ Total × 100 | 456 of 500 = 91.2% |