Percentage Calculator
Solve everyday percentage problems in one tap — no formulas to remember.
How to use the percentage calculator
Percentages show up everywhere — discounts, taxes, tips, exam scores, salary hikes and investment returns. This calculator handles the three questions people ask most often. Pick a mode, enter your two numbers, and get the answer with the working shown.
A% of B
Use this when you want a slice of a number, such as a 25% discount on a ₹200 item. The formula is:
result = (A ÷ 100) × B
So 25% of 200 is (25 ÷ 100) × 200 = 50.
A is what % of B
Use this to express one number as a percentage of another — for example, scoring 25 marks out of 200. The formula is:
result = (A ÷ B) × 100
Here 25 out of 200 is (25 ÷ 200) × 100 = 12.5%.
% change from A to B
Use this to measure growth or decline, such as a price rising from ₹25 to ₹200. The formula is:
result = ((B − A) ÷ A) × 100
Moving from 25 to 200 is ((200 − 25) ÷ 25) × 100 = 700%. A positive number means an increase and a negative number means a decrease.
For investment returns spread over several years, a single percentage change can be misleading — the CAGR calculator converts total growth into an annualised rate instead.
Everyday examples
- Discount: A ₹1,200 shirt at 30% off — 30% of 1,200 = ₹360 saved.
- Tip: A ₹800 bill with a 10% tip — 10% of 800 = ₹80.
- Exam: 68 marks out of 80 — 68 is 85% of 80.
- Salary hike: Pay rising from ₹50,000 to ₹57,500 — a 15% increase.
The table below shows the same three modes solving a wider spread of everyday problems. Every row is something you can reproduce in the calculator above.
| Question | Mode | Working | Answer |
|---|---|---|---|
| 18% GST on a ₹2,500 bill | A% of B | (18 ÷ 100) × 2,500 | ₹450 |
| 8% cashback on a ₹4,500 order | A% of B | (8 ÷ 100) × 4,500 | ₹360 |
| 45 marks out of 60 | A is what % of B | (45 ÷ 60) × 100 | 75% |
| Rent up from ₹15,000 to ₹16,500 | % change A to B | ((16,500 − 15,000) ÷ 15,000) × 100 | +10% |
| Salary cut from ₹9.5L to ₹8L | % change A to B | ((8 − 9.5) ÷ 9.5) × 100 | −15.8% |
Shopping bills in India often combine a discount with GST — once you know the percentage off, the GST calculator splits the base price and tax for you.
Percentage points vs percent
This is the single most misread number in Indian financial news. A percentage point is the plain arithmetic gap between two percentages, while a percent change measures that gap relative to the starting figure — they are not the same thing.
Suppose a bank raises its home loan rate from 8% to 9%. That is a rise of 1 percentage point, but it is a 12.5% increase in the rate itself, because (9 − 8) ÷ 8 × 100 = 12.5%. Both statements are correct; they simply answer different questions. Whenever an RBI repo-rate move or a revised fixed deposit rate is quoted, check whether the writer means points or percent before you compare offers.
Reverse percentage: finding the original amount
Sometimes you know the final figure and need to work backwards to the value before a discount or before tax was added. You cannot simply subtract the percentage — you have to divide.
If a jacket sells for ₹1,700 after a 15% discount, that price is 85% of the original (100% − 15%). So the original price is:
original = 1,700 ÷ 0.85 = ₹2,000
The same logic strips GST out of a tax-inclusive price. A ₹1,180 amount that already includes 18% GST is 118% of the base, so the pre-tax price is 1,180 ÷ 1.18 = ₹1,000 and the tax is ₹180. To confirm the split on any invoice, use the reverse mode of the GST calculator.
Successive percentages do not simply add up
Percentages applied one after another compound rather than sum. A 20% discount followed by an extra 10% off at the counter is not 30% off, because the second cut applies to the already-reduced price.
On a ₹1,000 item, 20% off gives ₹800, and 10% off ₹800 gives ₹720 — an effective discount of 28%, not 30%. The same trap appears with gains and losses: a 50% fall followed by a 50% rise leaves you at 0.5 × 1.5 = 0.75 of the start, a 25% loss overall. Because repeated returns multiply instead of add, the compound interest calculator is the right tool for stacking them over many periods, and the inflation calculator applies the same compounding to rising prices year after year.
Markup vs margin: two ways to quote a profit
Shopkeepers and freelancers often confuse these, and the difference changes the price you charge. Markup expresses profit as a percentage of the cost price, while margin expresses the same profit as a percentage of the selling price.
| Metric | Base | Formula | Example (cost ₹100, sell ₹150) |
|---|---|---|---|
| Markup | Cost price | (Profit ÷ Cost) × 100 | (50 ÷ 100) × 100 = 50% |
| Margin | Selling price | (Profit ÷ Sale) × 100 | (50 ÷ 150) × 100 = 33.3% |
The same ₹50 profit is a 50% markup but only a 33.3% margin. A margin can never exceed 100%, whereas a markup can — so always ask which base a quoted percentage uses before you set your price.
Common mistakes to avoid
- Confusing "A% of B" with "A is what % of B" — they answer different questions entirely.
- Using the new value instead of the original as the base for percentage change.
- Adding two discounts or two returns together instead of applying them one after another.
- Mixing up percentage points with percent change when comparing interest rates.