Percentage Calculator — Marks to Percentage, Grade & More
Calculate percentage from marks free — convert marks to percentage, find marks needed for a target percentage, calculate grade from percentage and more. Designed for students across all education levels. No sign-up.
Last updated: June 2026
What is % of ?
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is what percent of ?
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Percentage change from to
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Add % to
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Subtract % from
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Marks out of
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About this tool
Every percentage problem, solved
Percentages turn up everywhere — exam marks, discounts, taxes, tips, statistics, interest — but the exact calculation differs depending on what you're asking. This percentage calculator gathers the six most common operations into one clean, tabbed interface, so you can switch to the right one and get an instant answer instead of remembering which formula applies.
The first two modes are the everyday workhorses: what is X% of Y (for discounts, tips and shares of a total) and X is what percent of Y (for turning a part into a percentage, like a score). The third, percentage change, tells you the increase or decrease between two values — perfect for price changes, growth rates or before-and-after comparisons — and clearly labels which direction it went.
The next two handle adjustments: add X% to Y for things like adding sales tax or a markup, and subtract X% from Y for applying a discount or reduction. The final mode, marks to percentage, is built for students — divide your marks by the total and it returns the percentage along with the equivalent letter grade.
Each mode updates the moment you type, with no buttons to press, and every calculation runs entirely in your browser so nothing you enter is uploaded. It's a fast, free everyday utility for students, shoppers and anyone who works with numbers. Try the modes above, and explore the CGPA, GPA and grade calculators for academic-specific conversions.
How it works
Three quick steps — no account, nothing uploaded to a server.
Pick the operation
Choose from six percentage modes in the tabs.
Type your numbers
Fill in the values inline within the sentence.
Read the answer
The result updates instantly as you type.
FAQ
Frequently asked questions
How do I calculate a percentage of a number?
To find X% of Y, multiply Y by X and divide by 100 — for example, 20% of 150 is 150 × 20 ÷ 100 = 30. The first mode of this calculator does it instantly: enter the percentage and the number, and the answer appears as you type.
How do I work out what percentage one number is of another?
Divide the part by the whole and multiply by 100. For instance, 30 out of 150 is 30 ÷ 150 × 100 = 20%. The 'X is what % of Y' mode handles this — useful for turning marks, scores or amounts into a percentage.
How do I calculate percentage increase or decrease?
Subtract the old value from the new, divide by the old value, and multiply by 100. A rise from 80 to 100 is (100 − 80) ÷ 80 × 100 = 25% increase. The 'percentage change' mode shows whether the change is an increase or a decrease and by how much.
How do I convert marks to a percentage?
Divide your marks by the total possible marks and multiply by 100 — 425 out of 500 is 425 ÷ 500 × 100 = 85%. The 'marks to percentage' mode does this and also shows the equivalent letter grade.
Is the percentage calculator free and private?
Yes. All six modes are completely free with no sign-up, and every calculation runs in your browser, so nothing you enter is uploaded or stored.
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