Percentage Calculator
Calculate percentages, shares and percentage change in one place.
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The Percentage Calculator takes two numbers, X and Y, and answers the three questions people most often ask about them: what X% of Y is, what percentage X is of Y, and by how much Y has changed compared with X. It is handy for exam marks, discounts, tax, salary hikes, price changes and any report that asks for a share or a growth figure.
One pair of numbers, three answers
Fill in X and Y and press Calculate. Every result line is worked out from the same two numbers, so the job is to read the line that matches your question:
| Result line | Formula | X = 25, Y = 200 |
|---|---|---|
| X% of Y | X ÷ 100 × Y | 50 |
| X is what % of Y | X ÷ Y × 100 | 12.5% |
| % change X → Y | (Y − X) ÷ X × 100 | 700% |
All three are correct arithmetic, but usually only one makes sense for your situation. If you wanted 25% of 200, the 700% line is just noise. The first line shows up to four decimal places; the other two are rounded to two.
Everyday examples with real numbers
Marks as a percentage
You scored 432 out of 500. Enter X = 432 and Y = 500 and read the second line: 432 ÷ 500 × 100 = 86.4%. The first line, 432% of 500, answers a different question. For several subjects with different maximum marks, add the marks and the maximums separately before dividing, or use the exam marks percentage calculator.
A percentage of an amount
What is 18% of ₹2,450? Enter X = 18 and Y = 2450 and read the first line: 18 ÷ 100 × 2,450 = 441. The same line gives a tip, a commission, a down payment or the GST on a pre-tax price.
A salary hike
Monthly pay rises from ₹45,000 to ₹52,000. Put the old figure in X and the new one in Y and read the third line: (52,000 − 45,000) ÷ 45,000 × 100 = 15.56%. Now swap them. A fall from ₹52,000 to ₹45,000 is only −13.46%, because the change is measured against a bigger starting value. For this line, the order of X and Y matters.
Traps that catch people out
- Reversing a discount. A kurta costs ₹850 after 15% off. The original price is 850 ÷ 0.85 = ₹1,000, not 850 × 1.15 = ₹977.50. The 15% was taken from the original, so divide by the share that was left (85%).
- Successive changes. A price that rises 10% and then falls 10% does not return to where it started: 100 becomes 110, then 99. Enter X = 110 and Y = 99 and the change line confirms −10% for the second step, yet the overall change from 100 to 99 is −1%.
- Percent versus percentage points. If a loan rate goes from 8% to 9%, it has risen by 1 percentage point. With X = 8 and Y = 9 the change line shows 12.5%, which is the relative increase. Say which one you mean.
- A zero starting value. Growth from zero has no percentage, and nothing can be expressed as a percentage of zero. The calculator says so: with X = 0 the change line reads "Not defined (division by 0)", and with Y = 0 the second line does.
Mental shortcuts worth knowing
- 10% of a number: move the decimal point one place left. 10% of 2,450 is 245.
- 5% is half of 10%, and 15% is 10% plus 5%: 245 + 122.5 = 367.5 for 15% of 2,450.
- 1% moves the decimal point two places: 1% of 2,450 is 24.5, so 18% is 18 × 24.5 = 441, matching the worked example.
- X% of Y equals Y% of X. 20% of 50 and 50% of 20 are both 10, so pick whichever is easier to do in your head.
These shortcuts are good for checking a result at a glance. If the calculator's answer is far from your estimate, a number has probably gone into the wrong box.
When to use a different tool
For a sale price, the discount calculator applies the percentage and shows the amount saved in one step. For growth spread over several years, a single percentage change hides the yearly rate; an annual growth figure (CAGR) needs compounding, which this tool does not do. Percentages here are plain arithmetic on the numbers you type, so make sure both values describe the same thing, such as both monthly or both yearly figures, before comparing them.