Test Score Percentage Calculator: Marks Earned as a Percentage
Work out a test score as a percentage from the marks you earned and the total available — the standard way scores convert into a grade, with the percentage you missed shown alongside.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Score | Missed |
|---|---|---|
| 42 of 50 (84%) | 84.00% | 16.00% |
| 18 of 20 (90%) | 90.00% | 10.00% |
| 67 of 100 (67%) | 67.00% | 33.00% |
| 135 of 150 (90%) | 90.00% | 10.00% |
How This Calculator Works
Enter the marks you earned and the total marks on the test. The calculator divides one by the other and multiplies by 100 to give your percentage, with the percentage you got wrong shown next to it.
The Formula
Part as a Percentage of a Whole
Part is the portion, Whole is the total it belongs to
Worked Example
42 out of 50 is 84% — you missed 16%. On most US grading scales 84% is a solid B. If sections are weighted (say a final worth more than a quiz), this simple ratio doesn't apply directly — you'd weight each section first and total the points before converting. For straight point-counted tests, marks earned over marks available is exactly the percentage.
Key Insight
A raw score percentage is only the first step; what it means depends on the grading scale and whether the test is curved. The same 84% can be a B on a standard scale, an A on a generous one, or below the class median on a hard exam graded on a curve. Two practical notes: weighted assessments must be combined by weight (not just summed) before converting, and a few points often sit on a grade boundary — knowing you're at 84% versus 80% tells you exactly how many marks separate you from the next grade band, which is useful when deciding whether to contest a question or aim higher next time.
Frequently Asked Questions
How is a test score percentage calculated?
Divide the marks you earned by the total marks and multiply by 100. 42 out of 50 is 42 ÷ 50 × 100 = 84%.
What grade is 84%?
On a common US scale, 84% is a B (often a solid B or B+ depending on the school's bands). Grade boundaries vary by institution and some courses curve, so check your specific grading scale — the percentage is the input, the letter grade is the school's mapping.
How do I handle weighted sections?
This simple ratio assumes every mark counts equally. If a final is worth more than a quiz, multiply each section's percentage by its weight, add them up, and that weighted total is your real score. Use this calculator on the combined points only when all marks carry equal weight.
How many marks is one percent?
Divide 100 by the total marks. On a 50-mark test, each mark is 2 percentage points; on a 200-mark test, each mark is 0.5 points. That tells you exactly how many marks separate you from the next grade boundary.
What does the 'missed' figure mean?
It's the percentage you didn't score — 100 minus your score. At 84% you missed 16%. It's a quick way to see how far you are from full marks or from a target grade above your current score.
Related Calculators
Methodology & Review
The score percentage is marks earned divided by total marks, multiplied by 100. The complement is the percentage missed. It assumes every mark carries equal weight; weighted sections or partial credit must be totaled into the marks first.
Written by Ugo Candido · Last updated May 22, 2026.