A percentage is a number expressed as a fraction of 100 — the word literally means 'per hundred'. The calculator handles the five most common percentage problems: finding X% of a number, finding what percent one number is of another, percentage change between two values, and adding or subtracting a percentage from a number.
What is Percentage Calculator?
Percentages are everywhere — sales tax on a bill, a 20% discount on a shirt, the 30% income tax slab, a 12% return on a mutual fund, the 15% tip you leave at a restaurant. They all share a common idea: expressing a number as parts out of 100. The symbol % is a shorthand for 'divided by 100', so 25% just means 25/100 or 0.25.
Working with percentages confuses people more often than the math should warrant — usually because the same situation can be framed in different ways. 'Increase by 20%', 'add 20%', 'mark up by 20%', 'multiply by 1.2' — all mean the same thing. The calculator above strips out the wording and lets you pick the operation directly.
Mental percentage tricks are useful: 10% of any number is just shifting the decimal one place left. Half of that gives you 5%. Doubling 10% gives 20%. So 15% of ₹2,400 is just ₹240 + ₹120 = ₹360 — done in your head in two seconds. The calculator is for everything that does not yield to mental shortcuts.
Five percentage operations
Each mode in the calculator uses a different but related formula. Pick the one that matches your problem.
- X, Y
- Inputs—the two numbers in the problem
- A
- Original value—starting point in a percentage change
- B
- New value—ending point in a percentage change
How to use this calculator
Pick the mode that matches the question you want to answer. Each mode uses the two number inputs slightly differently.
Pick the mode
What is X% of Y, X is what % of Y, % change from A to B, increase by Y%, or decrease by Y%. The label of each mode tells you the question it answers.
Enter the first number
Depending on the mode, this is either X (the percentage), the original number, or the value being increased/decreased. The label updates per mode.
Enter the second number
The other input — Y, B, or the percent rate — depending on the mode you chose.
Read the result
The answer shows immediately, along with a one-line explanation showing the actual arithmetic. Useful for double-checking and for understanding the steps.
Common percentage scenarios
Sales and discounts
₹2,499 jacket marked '40% off' — pick decrease mode, enter 2499 and 40, get the final price.
Salary hike
Got a 12% raise on ₹85,000? Increase mode, 85000 and 12 — your new salary is shown instantly.
Stock price change
Bought at ₹420, now ₹487 — % change mode, 420 and 487 — gives the percentage gain.
Tip calculation
Bill of ₹1,840, 10% tip — find X% of Y mode, 10 and 1840 — gives the tip.
Marks to percentage
Scored 472 out of 600 — X is what % of Y mode, 472 and 600 — gives 78.67%.
Common mistakes to avoid
Subtracting a percentage to reverse an increase
If something went up 20%, going down 20% does not return to the original. ₹100 → ₹120 → ₹96, not ₹100. Use the reverse formula: divide, not subtract.
Computing % change with wrong base
Always divide by the original (starting) value. Going from 50 to 75 is +50% (25/50), not +33% (25/75).
Adding two percentages of different bases
5% of one quantity plus 10% of another is not 15% of anything. Compute each separately, add the results.
Glossary
- Percentage
- A number expressed as parts out of 100. The symbol % means 'divide by 100'.
- Percentage point
- The arithmetic difference between two percentages. Going from 4% to 6% is 2 percentage points.
- Markup
- An increase added to a base price, expressed as a percentage. ₹100 marked up 25% sells at ₹125.
- Discount
- A reduction from a base price, expressed as a percentage. ₹100 with a 25% discount sells at ₹75.
- Compound percentage
- When percentage changes happen successively — a 10% rise followed by a 10% fall is a 1% net loss, not zero.