Grade & GPA
Grade Scale Converter
Convert a mark out of any maximum to a mark out of 100 — with an optional curve.
Grade Scale Converter
About the Grade Scale Converter
Marks arrive on every maximum imaginable. Out of 20 for a quiz, out of 50 for a lab report, out of 150 for a final. This converter puts any of them on the same footing: enter your score and the maximum it was marked out of, and you get the percentage, the letter grade, the 4.0 GPA and the 10-point CGPA equivalent.
Two extras make it more useful than a division. Add a curve and the tool applies it and caps the result at 100%. Set your pass mark and it tells you whether you passed — and if not, exactly how many more marks you needed. That last number is often the one you actually want.
It also expresses your score on every other common maximum at once, so "16 out of 20" becomes "40 out of 50" and "120 out of 150" without a second calculation.
How to use the Grade Scale Converter
- Enter the marks scored and the maximum.
- Add a curve if your teacher applied one.
- Set the pass mark for your course.
- Select Convert.
- The table shows the same mark expressed out of 10, 20, 25, 50, 150 and 200.
The formula
Percentage = (score ÷ maximum) × 100
With a curve: add the curve to the percentage, then cap at 100.
Worked example
You scored 34 out of 50 on a test, and the instructor applied a 5-point curve.
Raw: (34 ÷ 50) × 100 = 68% — a D+.
Curved: 68 + 5 = 73% — a C.
The curve moved the result two full letter grades
At a 40% pass mark you cleared it either way, needing only 20 out of 50 to pass.
Marks out of 20, 50 and other common maximums
The conversions students look up most often, with the letter grade each lands on:
| Out of 20 | Out of 25 | Out of 50 | Percentage | Letter |
|---|---|---|---|---|
| 20 | 25 | 50 | 100% | A+ |
| 19 | 23.75 | 47.5 | 95% | A |
| 18 | 22.5 | 45 | 90% | A− |
| 17 | 21.25 | 42.5 | 85% | B |
| 16 | 20 | 40 | 80% | B− |
| 15 | 18.75 | 37.5 | 75% | C |
| 14 | 17.5 | 35 | 70% | C− |
| 13 | 16.25 | 32.5 | 65% | D |
| 12 | 15 | 30 | 60% | D− |
| 10 | 12.5 | 25 | 50% | F |
Note the bottom rows. A 50% is a fail in the US letter system but a comfortable pass in most Indian and UK-influenced systems, where the pass mark sits at 40% or 33%. Set the pass mark on the calculator to match your own institution rather than accepting the default.
What a grade curve does
A curve adjusts marks after the fact, usually because an assessment turned out harder than intended. The version this tool applies is a flat curve: every student gains the same number of points, capped at 100.
Instructors use other methods too, and it helps to know which one you are facing:
- Flat curve — add a fixed number of points to everyone. Simple and the most common.
- Top-score curve — the highest score becomes 100% and everything else scales up proportionally.
- Square-root curve — multiply the square root of the score by 10. Helps low scores far more than high ones.
- Bell curve — grades are distributed to a target shape, so your grade depends on the class, not just your work.
Only the flat curve is a simple addition. If your instructor uses one of the others, this tool converts your raw mark correctly but cannot predict the adjusted one.
How many marks you need to pass
Multiply the pass percentage by the maximum. Passing at 40% out of 150 needs 60 marks; passing at 33% out of 80 needs 26.4, so 27 in practice. The calculator does this and reports the shortfall directly when you have fallen short.
| Maximum | Pass at 33% | Pass at 40% | Pass at 50% | Pass at 60% |
|---|---|---|---|---|
| 20 | 6.6 | 8 | 10 | 12 |
| 50 | 16.5 | 20 | 25 | 30 |
| 75 | 24.75 | 30 | 37.5 | 45 |
| 100 | 33 | 40 | 50 | 60 |
| 150 | 49.5 | 60 | 75 | 90 |
Converting between two scales
Go through 100 rather than trying to jump directly. Convert the score to a percentage, then apply that percentage to the new maximum. A 16 out of 20 is 80%, and 80% of 50 is 40 — so 16/20 and 40/50 are the same result. The calculator lists these equivalents automatically.
For a full course grade built from several weighted assessments, use the grade calculator. For marks across multiple subjects, the marks percentage calculator is the right tool.
Grades out of 20 as percentages and letters
Many schools and countries mark out of 20. Multiply by 5 to get a percentage. Then read the letter grade from the common US scale.
| Score | Percentage | US letter grade |
|---|---|---|
| 20/20 | 100% | A |
| 19/20 | 95% | A |
| 18/20 | 90% | A− |
| 17/20 | 85% | B |
| 16/20 | 80% | B− |
| 15/20 | 75% | C |
| 14/20 | 70% | C− |
| 13/20 | 65% | D |
| 12/20 | 60% | D− |
| 10/20 | 50% | F |
In France and some other systems that mark out of 20, 10/20 is a pass, and 16/20 or above is excellent. A US letter grade is not a fair translation there — quote the original mark too.
Related guides
Other ways to use this calculator
- Convert marks to 100 and out of 100 calculator — rescale any mark to a score out of 100.
- Grade conversion calculator and mark conversion — turn a mark out of any total into a percentage, letter grade and GPA.
- Out of 20 grade — a 14 out of 20 grade is 70%, 15 out of 20 as a percentage is 75%, a 16 out of 20 grade is 80%, and the 17/20 letter grade is a B at 85%.
Frequently asked questions
Divide the score by 50 and multiply by 100. A 34 out of 50 gives (34 ÷ 50) × 100 = 68%. The same method works for any maximum — out of 20, out of 75, out of 150. Enter both numbers above and the tool also returns the letter grade, the GPA equivalent and the same score expressed on every other common maximum.
A curve adjusts marks upward after an assessment proves harder than intended. The most common version is a flat curve, where every student gains the same number of points — a 5-point curve turns 68% into 73%. Other methods exist: scaling the top score to 100%, square-root curves that help low scores most, and bell curves that fix the distribution. This tool applies the flat version.
Multiply the pass percentage by the maximum. Passing at 40% out of 150 needs 60 marks; at 33% out of 80 you need 26.4, so 27 in practice. Pass marks vary widely — 33% at Indian school level, 40% at many universities, 50% or 60% in US and UK systems. Set your own pass mark above and the calculator reports exactly how many marks short you are.
Yes, by routing through a percentage. Convert your score to a percentage first, then apply it to the new maximum. A 16 out of 20 is 80%, and 80% of 50 is 40, so 16/20 equals 40/50. Do not try to convert directly between two maximums — going through 100 keeps the arithmetic honest and the tool shows every common equivalent at once.
16 out of 20 is 80%, which is a B− on the common US scale. Multiply any score out of 20 by 5 to get the percentage: 15/20 is 75% (a C) and 17/20 is 85% (a B).
Sources and further reading
- Indiana University Registrar — Grading system — letter grade percentage bands
- University of Illinois Registrar — Courses and grades — grade point values used for the GPA equivalent
- Academic grading in the United States — how pass marks differ between national systems