This percentage calculator handles the six sums students meet most: X percent of Y, X as a percent of Y, increase, decrease, change and difference, and every one rests on the rule (part / whole) x 100. So 437 marks out of 500 is 437 / 500 x 100 = 87.4 percent, and 18 percent of 450 is 81.
Pick a mode, type two numbers and read the answer with the working shown. Further down sit each formula, a table of mental maths shortcuts, marks examples from school and college, and a list of every percentage page on this site with one line on what it does.
At a glance
Core rule
Percentage = (part / whole) x 100X% of Y
X / 100 x Y, so 18% of 450 = 81Increase or decrease
(new - old) / old x 100Difference
|a - b| / ((a + b) / 2) x 100Marks
marks obtained / maximum marks x 100Rounding
Keep two decimals; round only the final answer
Percentage = (Part / Whole) x 100
The part is the piece you are measuring, such as your marks. The whole is what it is measured against, such as the maximum marks.
How to use the percentage calculator above
Choose one of the six modes from the tabs. Each mode asks for two numbers and labels them, so you always know which box takes the old value and which takes the new one.
| Mode | What you type | Sample answer |
|---|---|---|
| X% of Y | 18 and 450 | 81 |
| X is what % of Y | 437 and 500 | 87.4% |
| Increase | old 62, new 74 | 19.35% rise |
| Decrease | old 80, new 68 | 15% fall |
| Change | old 250, new 215 | minus 14% |
| Difference | 72 and 88 | 20% |
The result panel prints the answer to two decimals and the line of working under it, so you can copy the steps into a notebook or check them on paper. Decimals are fine in every box. Leave out the percent sign and commas.
Percentage calculator formula for each mode
X% of Y = X / 100 x Y
X as a percent of Y = X / Y x 100
Percentage increase = (new - old) / old x 100
Percentage decrease = (old - new) / old x 100
Percentage change = (new - old) / old x 100, with a plus or minus sign
Percentage difference = |a - b| / ((a + b) / 2) x 100
Increase, decrease and change all divide by the old value, because they describe a move from a starting point. Difference has no starting point. It compares two equal partners, such as the cut offs of two shifts, so it divides by their average and drops the sign. When one value clearly came first, use change. When neither did, use difference.
Marks examples: school, board and college
Class 10 board, five subjects. Marks 92, 85, 78, 88 and 81 add up to 424 out of 500. 424 / 500 x 100 = 84.8 percent.
One semester. 612 out of 800 gives 612 / 800 x 100 = 76.5 percent.
Aggregate of three semesters. 540/700, 585/700 and 610/750. Add the marks (1,735) and the maximums (2,150): 1,735 / 2,150 x 100 = 80.70 percent. Averaging the three semester percentages (77.14, 83.57, 81.33) gives 80.68 instead, because the third semester carried more marks.
That small gap is why forms that ask for an aggregate or overall figure usually mean total marks over total maximum. The average percentage calculator shows both numbers side by side. For a full mark sheet with many subjects, the marks percentage calculator lets you add one row per paper.
Mental maths shortcuts for percentages
In an exam hall or a queue at the admission desk you may not have a phone. These shortcuts get you close in seconds. The worked column uses 640.
| Percent | Shortcut | 640 gives |
|---|---|---|
| 10% | Move the decimal one place left | 64 |
| 1% | Move it two places left | 6.4 |
| 5% | Half of 10% | 32 |
| 2% | Double 1% | 12.8 |
| 15% | 10% plus 5% | 96 |
| 20% | Double 10% | 128 |
| 25% | Divide by 4 | 160 |
| 12.5% | Divide by 8 | 80 |
| 50% | Halve it | 320 |
| 75% | Take away a quarter | 480 |
One more trick: X% of Y always equals Y% of X. 8% of 50 is hard in your head, but 50% of 8 is plainly 4, and the two are the same.
Marks to percentage table for common totals
Read across from the percentage you need to see the marks it takes on three common maximums. Five subjects make 500, six make 600, and many semesters total 800.
| Percentage | Out of 500 | Out of 600 | Out of 800 |
|---|---|---|---|
| 95% | 475 | 570 | 760 |
| 90% | 450 | 540 | 720 |
| 85% | 425 | 510 | 680 |
| 80% | 400 | 480 | 640 |
| 75% | 375 | 450 | 600 |
| 70% | 350 | 420 | 560 |
| 65% | 325 | 390 | 520 |
| 60% | 300 | 360 | 480 |
| 55% | 275 | 330 | 440 |
| 50% | 250 | 300 | 400 |
| 40% | 200 | 240 | 320 |
| 33% | 165 | 198 | 264 |
For any other total, the percentage to marks calculator runs the reverse sum.
Every percentage tool on this site
Each page below goes deeper into one kind of sum, with its own worked examples and mistakes table.
| Page | What it does |
|---|---|
| Marks percentage calculator | Adds subject marks and gives the overall percentage |
| How to calculate percentage | The method by hand and on a basic or phone calculator |
| Percentage kaise nikale | The same method explained in simple Hinglish |
| Percentage increase calculator | How much a value rose, in percent |
| Percentage decrease calculator | How much a value fell, in percent |
| Percentage change calculator | Signed change from old to new, plus variance |
| Percentage difference calculator | Gap between two values with no starting point |
| Average percentage calculator | Simple and weighted average of several percentages |
| Percentage to marks | Turns a percentage back into marks for any total |
| Percentage formulas for spreadsheets | Cell formulas for a whole class mark sheet |
For board results, the 10th and 12th percentage pages handle best of five. If your grade card shows a CGPA instead of marks, start at CGPA to percentage.
Money, targets and other everyday uses
The tool is a general number to percentage calculator, so it is not limited to marks. Because the rule never changes, it works as a school percentage calculator, a college percentage calculator and a degree percentage calculator alike, and it handles ITI and diploma results and Class 10 or 12 totals once you know which subjects count. A few other uses students ask about:
- CTC hike. Use the increase mode as a CTC percentage calculator: if the yearly figure on an offer letter goes from 45 units to 54 units, the rise is 9 / 45 x 100 = 20 percent, whatever the units are.
- Target vs achievement. A sales intern who closes 102 against a target of 120 has reached 102 / 120 x 100 = 85 percent.
- Win percentage. A college team that wins 14 of 20 matches has a 70 percent win rate.
- Amount of a share. The X% of Y mode is an amount percentage calculator too, so if 12 percent of a 2,500 point scholarship test score is the essay section, that section is worth 300 points.
Whatever the context, the same tool doubles as a total, aggregate or overall percentage calculator: put the part on top and the whole underneath.
Common percentage mistakes
| Error | Where it goes wrong | Correct habit |
|---|---|---|
| Dividing by the new value for an increase | The base of a change is where you started | Divide by the old value |
| Averaging subject percentages with different maximums | Small papers get too much weight | Sum the marks and the maximums separately, then divide once |
| Rounding each step | Errors pile up | Round only the final figure |
| Calling 60% to 66% a 6% rise | That is 6 percentage points, a 10% rise | Say points for the gap, percent for the ratio |
| Treating percentile as percentage | Percentile ranks you against others | Use a percentile tool for exam ranks |
Percentage, percentage points and percentile
A percentage compares a part with a whole. Percentage points compare two percentages by plain subtraction: going from 72 percent to 78 percent is a gain of 6 points. A percentile is something else again. In NTA exams it is the share of your shift whose raw score is equal to or below yours, so a 92 percentile does not mean 92 percent marks. The JEE Main percentile page explains that rule.
Keep these three apart on forms. A college asking for your Class 12 percentage wants marks over maximum, not a percentile and not a CGPA.
Questions students ask
How do I calculate percentage of marks?
Take your total score, split it by the total maximum and scale the result up by 100. A score of 424 against 500 is 84.8 percent. The marks mode of the calculator above does it in one step.
What is the formula used by this percentage calculator?
Every mode rests on part / whole x 100. Increase, decrease and change use the old value as the whole. Difference uses the average of the two values.
How do I find 15% of a number quickly?
Take 10 percent by moving the decimal one place left, halve that for 5 percent, and add the two. For 640, that is 64 + 32 = 96.
Is aggregate percentage the same as the average of semester percentages?
Only when every semester has the same maximum marks. Otherwise total marks over total maximum gives the true aggregate, and the plain average drifts slightly.
Does this work as a 10th or 12th percentage calculator?
Yes for the arithmetic. For board results where the receiving college picks your best five subjects, the 10th and 12th percentage pages let you choose the subjects.
What is the difference between percentage change and percentage difference?
Change measures a move from an old value to a new one and divides by the old value. Difference compares two values that have no order and divides by their average.