Example 1
- Mode: one test
- Earned 42, maximum 50
84% (B)
42 / 50 × 100 gives 84%, letter B on the US sketch.
Grade calculator
Pick a test, a weighted mean, or a final. Percent is earned over maximum times 100. 42 of 50 is 84% and B. Letter A starts at 90. Not a gradebook.
Percent of a number: percentage of a number. Plain mean: arithmetic mean. Here we add a US letter sketch and a needed-on-final mode. Not a school gradebook.
Result
Type scores and weights. The average shows up here.
How it works
The calculator does three jobs from the numbers you type. On a test, percent is earned divided by maximum times 100. 42 of 50 give 84. 18 of 20 give 90. 9 of 20 give 45. The letter beside the result is a US sketch: A from 90, B from 80, C from 70, D from 60, otherwise F. That is not a 2 to 6 scale and not a transcript mark.
The weighted mean is score times weight, summed, then divided by the sum of the weights you typed. 80 at 40 and 90 at 60 give 86, because 3200 plus 5400 is 8600, and 8600 divided by 100 is 86. Weights need not sum to 100: 75 at 10 and 85 at 30 give 82.5, because we divide by 40, not by one hundred. A blank score or a blank weight skips the row. A weight of zero adds nothing. Four rows are the form cap, not the cap of a term.
On a final, the needed percent is the target minus current times the share of the course that is not the final, then divided by the final weight. Current 80, weight 20, target 80 gives 80 on the exam. Current 70, weight 20, target 90 gives 170: impossible with that weight. Current 95, weight 10, target 85 goes negative, so you are already there. A final weight of 0 does not divide.
Extra credit above the maximum is allowed in test mode when the maximum is positive: 22 of 20 give 110%, and the letter still sits on A, because A starts at 90. Zero earned with a positive maximum is 0%. A comma and a period are the same decimal: 18.5 of 20 matches 18,5.
The metric and US switch does not multiply 42 or 50. The header money symbol does not turn 84% into an amount, because there is no money here. Percent of a number without a test lives on a separate page. A plain arithmetic mean without US letters has its own card too.
A percent from the points you type, with no gradebook and no campus rounding rule. Type 42 and 50, click Calculate, and match 84% and B. Then 80 at 40 and 90 at 60 for 86%. The numerator sum is Σ of the scores you type.
How to use
- Pick a mode: one test, a weighted mean, or the percent needed on the final.
- On a test type points earned and the maximum. 42 of 50 give 84% and letter B. 18 of 20 give 90% and A, because A starts at 90.
- For a weighted mean fill a score and a weight in a row. A blank score or a blank weight skips that row. Weights need not sum to 100.
- For a final enter current average, exam weight, and the target. 80, 20, and 80 give 80 on the exam. 70, 20, and 90 give 170, which is unreachable.
- Read the percent and the US letter. It is an A to F sketch, not a 2 to 6 mark and not a row in a gradebook.
Formula
percent = earned / maximum × 100
Weighted mean = Σ(score × weight) / Σ(weight). A blank score or a blank weight skips the row. Weights need not sum to 100.
Needed on the final = (target − current × (1 − final weight/100)) / (final weight/100). Above 100: impossible with this weight. Below 0: already there. US letters: A ≥ 90, B ≥ 80, C ≥ 70, D ≥ 60, else F. A sketch, not a 2 to 6 scale.
84% and B from 42 of 50
Percent is earned over maximum times 100. 42 of 50 is 84% and B. Letter A starts at 90.
- %
- Test result: 42 / 50 × 100 = 84. 18 of 20 is 90. 9 of 20 is 45. A sketch, not a gradebook.
- A
- The letter from 90 in this calculator’s US sketch. 18 of 20 = 90% gets A. 84% stays at B.
- B
- The 80-89 band. 42 of 50 = 84% is B. Weights 80 at 40 and 90 at 60 also give 86% and B.
- F
- Below 60. 9 of 20 = 45% is F. A 2-to-6 scale does not enter here.
- Σ
- The sum in the weighted mean: Σ(score × weight) / Σ(weight). 75 at 10 and 85 at 30 is 82.5, because the denominator is 40.
Examples
Example 2
- Mode: one test
- Earned 18, maximum 20
90% (A)
18 / 20 × 100 gives 90%, the A cutoff from ninety.
Example 3
- Mode: one test
- Earned 9, maximum 20
45% (F)
9 / 20 × 100 gives 45%, under 60 so F.
Example 4
- Mode: weighted mean
- 80 at 40 and 90 at 60
86% (B)
(80×40 + 90×60) / 100 gives 86%, letter B.
Example 5
- Mode: weighted mean
- 75 at 10 and 85 at 30
82.5% (B)
(75×10 + 85×30) / 40 gives 82.5%, weights sum to 40.
Example 6
- Mode: needed on the final
- Current 80, weight 20, target 80
80% (B)
Needed gives 80% on the exam, the same B cutoff.
Example 7
- Mode: needed on the final
- Current 70, weight 20, target 90
170% (impossible)
Needed gives 170%, so a 90 target is impossible at weight 20.
Example 8
- Mode: needed on the final
- Current 95, weight 10, target 85
-5% (already there)
Needed gives -5%, so target 85 is already there at this weight.
Frequently asked questions
What percent is 42 of 50, and which letter?
42 / 50 × 100 = 84%. On the US sketch that is B, because A starts at 90. 18 of 20 is 90% and A. 9 of 20 is 45% and F.
Is letter A to F a transcript mark on a 2 to 6 scale?
No. It is a US sketch: A from 90, B from 80, C from 70, D from 60, otherwise F. We do not turn 86% into a four.
Do weights in the mean have to sum to 100?
No. We divide by the sum of the weights you typed. 75 at 10 and 85 at 30 give 82.5, because the denominator is 40. A blank weight skips the row.
What if the final need comes out above 100%?
With that weight the target is unreachable. 70 now, weight 20, target 90 gives 170. Raise the final weight or lower the target.
What does a negative result mean in final mode?
You are already at the target with that weight. 95 now, weight 10, target 85 gives -5. You do not need exam points to keep 85.
Does this write marks into a school gradebook?
No. We only compute what you type. There is no link to Canvas, PowerSchool, or any SIS.
How is this different from percentage of a number?
That page is a% of b, with no letters and no course weights. Here 42 of 50 is a test, plus a weighted mean and a final formula.
Are points above the maximum an error?
Not in test mode. 22 of 20 give 110%. The letter still sits on A, because A starts at 90.
Does a comma in 18.5 work like a period?
Yes. 18.5 of 20 matches 18,5 of 20. Avoid thousand separators inside the number.
Does the US switch multiply 42 or 50?
No. A percent stays a percent. The header money symbol does nothing either, because there is no amount here.
Knowledge sources
Percent is earned / max × 100. The A–F letter is a US sketch scale, not a transcript grade.
Page updated in 2026.