Percentage Calculator
Marks, discounts and changes. A little less mental maths.
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Your result
A little input.
And we’ll take it from here.
How to use it
Choose a calculation, enter the two numbers, and see the result.
A quick example
To find your marks percentage, select “A is what % of B?” and enter 450 and 500. Result: 90%.
Good to know
Percentage change divides the difference by the starting value. It is undefined when that starting value is zero.
Is it free?
Yes. No account, payment or file upload to a server is needed.
Common percentage mistakes
Percentages don't add up across subjects
Your overall percentage is total marks divided by total maximum marks, not the average of each subject's percentage, unless every subject has the same maximum.
Discounts on discounts
'40% + 10% off' is not 50% off. The second discount applies to the already-reduced price, so the total is 46%. Work it out in two steps.
CGPA conversion depends on the board
Converting CGPA to a percentage uses a formula set by each board or university. For example, CBSE has used multiplying by 9.5. Use the official formula from your board, not a general percentage calculation.
A little more clarity
How do I calculate my marks percentage?
Select “A is what % of B?”. Put your marks in A and the maximum possible marks in B. For 450 out of 500, the calculation is 450 ÷ 500 × 100 = 90%. The maximum marks cannot be zero.
What is the difference between percentage change and percentage points?
An increase from 20% to 30% is 10 percentage points, but a 50% relative increase. This tool’s percentage-change mode calculates (B − A) ÷ |A| × 100. Use positive starting values for ordinary price, salary and growth comparisons.
Read our guide: percentages in marks, discounts and GST.
Maintained by BLRGO · Updated 27 September 2026 · Report a problem