Converting a raw score into a percentage is one of the most common calculations students and teachers need to do. Whether it's a class test, a mock exam, coursework or a professional assessment, the method is the same and takes about five seconds once you know the formula.
The Basic Formula
To convert any score to a percentage:
You scored 36 out of 45 on a maths test.
Percentage: (36 ÷ 45) × 100 = 80%
You answered 17 out of 25 questions correctly on a quiz.
Percentage: (17 ÷ 25) × 100 = 68%
Weighted Scores and Multiple Sections
Many assessments have multiple sections with different maximum scores. To find your overall percentage, you need to combine them correctly — not just add up the percentages from each section, because sections with more marks carry more weight.
The right method: add all marks obtained, add all total marks available, then divide.
Section A: 28/40 | Section B: 17/25 | Section C: 9/15
Total marks: 28 + 17 + 9 = 54
Total available: 40 + 25 + 15 = 80
Overall percentage: (54 ÷ 80) × 100 = 67.5%
If you had averaged the three percentages separately (70% + 68% + 60%) ÷ 3 = 66%, you'd get a slightly different and technically incorrect answer, because the three sections have different weights. Always combine raw scores first.
UK Degree Grade Boundaries (for Reference)
In the UK, undergraduate degrees typically use the following percentage boundaries, though these vary by institution:
- First class (1st): 70% or above
- Upper second class (2:1): 60–69%
- Lower second class (2:2): 50–59%
- Third class (3rd): 40–49%
Individual universities and departments may use different boundaries or apply a weighting formula that considers year of study. Always check your institution's specific regulations.
Converting Marks to GPA (for US or International Contexts)
If you're converting a UK percentage to a US GPA scale (which typically runs from 0.0 to 4.0), there's no universal standard, but a common approximation is:
- 90–100% → 4.0 (A)
- 80–89% → 3.0–3.9 (B)
- 70–79% → 2.0–2.9 (C)
- 60–69% → 1.0–1.9 (D)
- Below 60% → 0.0 (F)
Universities and employers evaluating international qualifications usually have their own conversion tables. Use these only as a rough guide.
How Much Does Each Question Affect Your Score?
If you want to understand how much each mark is worth as a percentage of the total, divide 100 by the total number of marks. On a 40-mark paper, each mark is worth 100 ÷ 40 = 2.5 percentage points. Knowing this helps you triage which questions to prioritise under time pressure.
40-mark exam. Each mark = 2.5%. Getting the last 4 marks right (for example, completing an unfinished question) adds 10 percentage points to your total.
What Score Do I Need to Reach a Target Percentage?
To work out the minimum marks you need to achieve a target percentage:
Exam total: 60 marks. You want to achieve at least 70%.
Required marks: (70 ÷ 100) × 60 = 42 marks
Convert any score to a percentage instantly using the "X is what percent of Y?" calculator on PercentageHQ.
Score to Percentage Calculator →Quick Reference
- Score to percentage: (Marks ÷ Total) × 100
- Multiple sections: combine raw scores before dividing
- Marks needed for a target: (Target% ÷ 100) × Total
- Value of one mark: 100 ÷ Total marks
Grade boundary information is provided for general reference only. Always check your specific institution's regulations for official grade thresholds.