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Math & School
Grade Calculator — Points to Percentage and Letter Grade
Turn raw points into a percentage and letter grade on the standard US scale
A grade calculator answers the question every American student types into a search bar after handing in an assignment: "I got this many points out of that many — what grade is that?" The math is the foundation of every report card, online gradebook and syllabus in US schools, and it comes down to a single ratio.
The core formula is simply your points earned divided by points possible, times 100:
Grade % = (points earned ÷ points possible) × 100
So a quiz where you got 45 out of 50 is 45 ÷ 50 × 100 = 90%, which lands on an A− on a plus/minus scale (or a flat A on a straight scale). A bigger test scored 270 out of 300 works out to exactly the same thing: 270 ÷ 300 × 100 = 90% = A−. The point total doesn't matter — only the ratio does.
Once you have the percentage, you convert it to a letter grade on the standard US scale:
• A = 90–100, B = 80–89, C = 70–79, D = 60–69, F = below 60.
Most US schools refine that with plus/minus bands — an 88% is a B+, an 82% is a B−, a 91% is an A− — and this calculator shows both the broad letter and the plus/minus version so it matches whatever your teacher uses.
Where a single assignment becomes a course grade, points alone aren't enough, because syllabi rarely count everything equally. A common breakdown might be homework 20%, quizzes 30%, tests 50%. To handle that, switch on weighted categories: enter your average percentage in each category and the weight it carries, and the calculator blends them into one final course grade using a weighted average — exactly how your learning-management system (Canvas, PowerSchool, Google Classroom, Infinite Campus) computes it behind the scenes.
The most common mistake students make is averaging category percentages straight across — treating a 95% homework average and a 70% test average as a flat 82.5% — when the syllabus actually weights tests far more heavily. With tests at 50% and homework at 20%, that same student is closer to a 79%, a full letter lower. Weighting is the whole game once categories are involved.
Note that this is the grade percentage calculator: it tells you what a score is. If instead you want to know what you need on the final exam to hit a target grade, use a final grade calculator; if you're scoring a test by counting how many questions you got right, use a test score calculator. This tool owns the everyday "points-to-grade" conversion.
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Calculator
Fill in the fields and click "Calculate" for instant results.
📰 Formula
• Grade % = (points earned ÷ points possible) × 100 • Letter grade: A = 90–100, B = 80–89, C = 70–79, D = 60–69, F = below 60 • Plus/minus bands: 97+ = A+, 93–96 = A, 90–92 = A−, 87–89 = B+, 83–86 = B, 80–82 = B−, and so on • Weighted course grade = Σ (category % × category weight) ÷ Σ (weights)
📰 Formula
• Grade % = (points earned ÷ points possible) × 100 • Letter grade: A = 90–100, B = 80–89, C = 70–79, D = 60–69, F = below 60 • Plus/minus bands: 97+ = A+, 93–96 = A, 90–92 = A−, 87–89 = B+, 83–86 = B, 80–82 = B−, and so on • Weighted course grade = Σ (category % × category weight) ÷ Σ (weights)
🧪 Worked examples
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Example 2
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Example 3
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Example 4
⚠️ Common mistakes
- Averaging category percentages straight across instead of weighting them by the syllabus.
- Comparing raw points (10/10 vs 90/100) instead of the percentage — only the ratio sets the grade.
- Forgetting that a plus/minus scale splits each letter, so an 88% (B+) and an 82% (B−) are different.
- Entering points possible as zero, which makes the percentage undefined.
- Mixing up a points total with a percentage — a 47-point score isn't 47% unless it was out of 100.
💡 Tips
- Only the ratio matters: 9/10 and 90/100 are both exactly 90%.
- When categories are weighted, the high-weight bucket (usually tests) moves your grade the most.
- Check your syllabus for the exact cutoffs — some schools set A at 93+ rather than 90+.
- To see what one more assignment does, add its points to both the earned and possible totals and recompute.
Embed this calculator on your site
Copy the code below and paste it into the HTML of your site or blog.
<iframe src="https://www.calcnimbus.com/embed/grade-calculator" width="100%" height="500" frameborder="0" style="border:1px solid #eee;border-radius:12px"></iframe>
❓ Frequently asked questions
How do I calculate my grade as a percentage?
Divide the points you earned by the points possible, then multiply by 100. For example, 45 out of 50 = 45 ÷ 50 × 100 = 90%.
What letter grade is 45 out of 50?
45 out of 50 is 90%, which is an A− on a plus/minus scale or a flat A on a straight A–F scale. It sits right at the bottom of the A range.
What are the standard US grade percentage cutoffs?
A = 90–100, B = 80–89, C = 70–79, D = 60–69, and F = below 60. Many schools add plus/minus bands, such as A− for 90–92 and B+ for 87–89.
What is the difference between a weighted and unweighted course grade?
An unweighted grade averages every assignment equally. A weighted grade multiplies each category's average by its syllabus weight — for example homework 20%, quizzes 30%, tests 50% — so tests count more than homework toward the final.
How do I calculate a weighted grade with categories?
Multiply each category's average percentage by its weight, add those products, and divide by the total weights. Homework 95% × 0.20 + Quizzes 85% × 0.30 + Tests 78% × 0.50 = 83.5%.
Does the number of points change my grade?
No — only the ratio does. A 9 out of 10 and a 90 out of 100 are both 90%. A test worth more points carries more weight in a points-based gradebook, but the percentage for that one test is still earned ÷ possible.
Is an 89 an A or a B?
On the standard US scale an 89% is a B (specifically a B+), because the A range starts at 90%. A few schools round up or set lower cutoffs, so check your syllabus if you're on the edge.
How is this different from a final grade calculator?
This grade calculator tells you what a score is worth right now as a percentage and letter. A final grade calculator works backward to find the score you need on a remaining exam to reach a target grade.
Do my category weights have to add up to 100%?
Ideally yes, but this calculator normalizes them, so weights of 20/30/50 and 2/3/5 give the same result. If your weights don't sum to 100, it divides by their actual total to keep the math correct.