To calculate your grade, divide the points you earned by the total points possible and multiply by 100. A score of 42 out of 50 is 42 ÷ 50 × 100 = 84%, which is a B on the standard A–F scale. For a whole course with weighted categories, take each category's average, multiply by its weight, and add them up.
Key takeaways
- Percentage = points earned ÷ points possible × 100.
- 42 / 50 → 84% → B on the default scale.
- Average equal-weight assignments; weight unequal categories by their percent.
- Letters use A 90+, B 80+, C 70+, D 60+, F below 60.
- These are estimates — confirm your school's official scale and rounding.
The one formula behind every grade
A grade is a ratio dressed up as a percent. Take what you earned, divide by what was possible, and scale to 100. It works for a single quiz, a unit test, or any one assignment.
If you only know how many questions you got wrong, subtract the wrong from the total to get the number correct first. The easy grader does exactly that — type the question count and the number missed and it stamps the percent and letter.
Worked example: 42 out of 50
You scored 42 points on a test worth 50. Divide: 42 ÷ 50 = 0.84. Multiply by 100: 84%. On the standard scale, 84% sits in the 80–89 band, so it is a B. Earn two more points (44 / 50) and you reach 88% — still a B, but close to the 90% A cutoff. The percentage grade calculator turns any points-earned and points-possible pair into a percent and letter instantly.
Standard A–F grading scale
| Letter | Percentage | GPA points (4.0) |
|---|---|---|
| A | 90–100% | 4.0 |
| B | 80–89% | 3.0 |
| C | 70–79% | 2.0 |
| D | 60–69% | 1.0 |
| F | Below 60% | 0.0 |
This is the most common US scale. Many schools add plus/minus grades or shift the cutoffs — always confirm your class's official scale.
Your overall course grade
One test is easy; a whole course is where students get tripped up. If every assignment counts equally, just average the percentages. But most syllabi weight categories — say tests 50%, homework 30%, quizzes 20%. In that case, multiply each category's average by its weight, add the results, and divide by the total weight.
For example, with a 90% test average (×0.50), 80% homework (×0.30), and 100% quizzes (×0.20): 45 + 24 + 20 = 89%. The weighted grade calculator handles any set of category weights, and the average grade calculator covers the simpler equal-weight case.
Frequently asked questions
How do I calculate my grade as a percentage?
Divide the points you earned by the total points possible, then multiply by 100. For example, 42 out of 50 is 42 ÷ 50 × 100 = 84%, a B on the standard scale.
How do I work out my overall course grade?
If everything is weighted equally, average the percentages. If categories carry different weights, multiply each category average by its weight, sum them, and divide by the total weight — the weighted grade calculator does this for you.
What grade is 42 out of 50?
42 ÷ 50 = 0.84 = 84%, which is a B on the default A–F scale.
Sources: the percentage-grade calculation (earned ÷ possible × 100) and weighted-average method are standard arithmetic. Letter-grade bands use the common US scale (A 90+, B 80+, C 70+, D 60+, F below 60); individual schools and districts set their own cutoffs, plus/minus grades, and rounding rules.
Last reviewed 2026-06-28