You scored 39 out of 45 on a test. What percentage is that, and is it a B or a B+?
39 out of 45 equals 86.67%. On the standard U.S. 10-point scale, that is a B, worth 3.0 GPA points. It sits 0.33 points below the 87% B+ line, so schools that round to the nearest whole percent will call it a B+ (3.3 GPA).
This guide covers the percentage, letter grade, GPA, why rounding decides this score, and what a 39/45 means inside a weighted course.
Key Takeaways
- 39 out of 45 = 86.67%, which is a B (83–86%) with exact decimals, or a B+ (87–89%) if rounded to 87%.
- On the 4.0 GPA scale, a 39/45 converts to 3.0 GPA points, or 3.3 at a school that rounds up.
- Each question on a 45-point test is worth 2.22%. One more correct answer (40/45 = 88.89%) is a clear B+.
What Is 39 Out of 45 as a Percentage?
Formula:
(Points Earned ÷ Total Points) × 100 = Percentage Grade
Applied:
(39 ÷ 45) × 100 = 0.8667 × 100 = 86.67%
You can simplify the fraction first: 39/45 = 13/15, which is 0.8667. To learn the method for any score, see how to calculate grade percentage, or check any result with the percentage calculator.
Worked Step-by-Step Examples
Example 1: Basic Percentage Conversion
A student misses 6 questions out of 45 and scores 39/45.
- Step 1: Divide points earned by total points → 39 ÷ 45 = 0.8667
- Step 2: Multiply by 100 → 0.8667 × 100 = 86.67%
- Step 3: Match it to the letter scale → B (exact) or B+ (rounded)
Example 2: How Close Is 39/45 to the Next Tier?
- Points needed for 83% (B): 45 × 0.83 = 37.35 → you earned 39, so you clear it by 1.65 points.
- Points needed for 87% (B+): 45 × 0.87 = 39.15 → you are 0.15 points short.
- Next whole score up: 40/45 = 88.89%, a B+.
That is a very small gap. A 0.15 point shortfall is why your teacher’s rounding rule matters more here than on most scores. One fewer correct answer, 38/45, is 84.44%, a B.
Example 3: A 39/45 Test Inside a Weighted Course Average
Say a student has:
- Homework (20% of grade): 88%
- Test (30% of grade): 86.67% (their 39/45)
- Final Exam (50% of grade): 85%
Weighted Grade = (Score₁ × Weight₁) + (Score₂ × Weight₂) + (Score₃ × Weight₃)
Weighted Grade = (88 × 0.20) + (86.67 × 0.30) + (85 × 0.50) = 17.6 + 26.0 + 42.5 = 86.1%
The course grade lands at a B. See how to calculate weighted average grades for the full method.
Quick-Reference Grade Table (x/45 Scores)
| Score | Percentage | Letter Grade | GPA Points |
|---|---|---|---|
| 45/45 | 100.00% | A+ | 4.0 |
| 42/45 | 93.33% | A | 4.0 |
| 41/45 | 91.11% | A– | 3.7 |
| 40/45 | 88.89% | B+ | 3.3 |
| 39/45 | 86.67% | B (B+ if rounded) | 3.0 (3.3) |
| 38/45 | 84.44% | B | 3.0 |
| 37/45 | 82.22% | B– | 2.7 |
| 36/45 | 80.00% | B– | 2.7 |
| 35/45 | 77.78% | C+ | 2.3 |
| 34/45 | 75.56% | C | 2.0 |
| 32/45 | 71.11% | C– | 1.7 |
| 27/45 | 60.00% | D– | 0.7 |
| 26/45 | 57.78% | F | 0.0 |
Percentage-to-Letter Grade Scale Used Above
| Percentage Range | Letter Grade | Performance Level |
|---|---|---|
| 97% – 100% | A+ | Outstanding |
| 93% – 96% | A | Excellent |
| 90% – 92% | A– | Excellent |
| 87% – 89% | B+ | Very Good |
| 83% – 86% | B | Good (39/45 falls here, at the very top) |
| 80% – 82% | B– | Above Average |
| 77% – 79% | C+ | Above Average |
| 73% – 76% | C | Average |
| 70% – 72% | C– | Below Average |
| 67% – 69% | D+ | Poor |
| 63% – 66% | D | Barely Passing |
| 60% – 62% | D– | Barely Passing |
| Below 60% | F | Failing |
This is the standard 10-point scale used by most U.S. schools. On a stricter 7-point scale, 86.67% is a B (the B range there is 85–92%). Compare your school’s cutoffs with the grade scale and grading chart guides, or see different grading scales.
What GPA Is 39 Out of 45?
On the standard unweighted 4.0 scale, a B converts to 3.0 GPA points. At schools that round 86.67% up to 87%, it becomes a B+ and converts to 3.3. Schools without plus/minus grades count it as a flat 3.0.
Weighted vs. Unweighted Impact
| Course Level | GPA Bonus | B (86.67%) GPA Value | B+ (if rounded) GPA Value |
|---|---|---|---|
| Standard | +0.0 | 3.0 | 3.3 |
| Honors | +0.5 | 3.5 | 3.8 |
| AP / IB | +1.0 | 4.0 | 4.3 |
Learn how bonuses work in how to calculate GPA with weighted grades. Run your own numbers in the GPA calculator.
Is 39 Out of 45 a Good Grade?
Yes. An 86.67% is above the typical class average of 75–80% and counts as a good grade at virtually every school.
How Rounding Affects a 39/45
This score sits right on the B/B+ line, so school policy decides the letter:
| Policy | 86.67% Becomes | Letter | GPA |
|---|---|---|---|
| Round to the nearest whole percent | 87% | B+ | 3.3 |
| Truncate (drop decimals) | 86% | B | 3.0 |
| Use exact decimals | 86.67% (below 87) | B | 3.0 |
Ask your teacher which policy applies, because the same test gives two different letters. For a similar close call, see is 89.5 an A or B?
International Grade Comparison
| Country / System | Approximate Equivalent of 39/45 (86.67%) |
|---|---|
| United States | B / B+ (3.0–3.3 GPA) |
| United Kingdom (university) | First-class (70%+) |
| France (0–20 scale) | 17.33/20 — Très Bien |
| Germany (1.0–5.0, 1 best) | About 1.3–1.7 — Sehr gut to Gut |
| Canada | A (80–89% in many provinces) |
The same score can look very different depending on the country. An 87% is a first-class result at a UK university and an A in many Canadian provinces, but a B or B+ in the U.S.
Practical Tips: Raising a 39/45 to a Clear B+ or A–
- Review the 6 missed questions. Look for patterns: one topic, one question type, or time pressure.
- Ask about partial credit. On a 45-point test, half a point is worth 1.11%. Just 0.15 more points would reach 87%.
- Ask about the rounding rule. It could turn your B into a B+ without any extra work.
- Know how much the test counts. See how much is a test grade worth before deciding how much effort to spend.
- Plan ahead. Use a what grade do I need calculator to see what you need on future work to reach your target grade.
- Teachers: if a test average looks low, consider curving test grades.
Frequently Asked Questions (FAQ)
1. What is 39 out of 45 as a percentage?
39 divided by 45 equals 0.8667, which multiplied by 100 gives 86.67%. This is the standard formula for turning any fraction score into a percentage.
2. What letter grade is 39 out of 45?
On the standard 10-point U.S. scale, 86.67% is a B with exact decimals. It becomes a B+ if your school rounds to the nearest whole percent (87%).
3. What GPA is 39 out of 45?
A B is worth 3.0 GPA points on the unweighted 4.0 scale. A rounded B+ is worth 3.3.
4. Is 39 out of 45 a good grade?
Yes. It’s a good score, well above the typical class average, and sits right at the top of the B range.
5. Is 39 out of 45 a B or a B+?
It depends on rounding. With exact decimals it is a B (86.67% is below 87%). If your school rounds to the nearest whole number, it is a B+.
6. How many points do I need for a B+ on a 45-point test?
For 87%, you need 39.15 points. With whole points, that means 40/45 (88.89%).
7. What is 39 out of 45 out of 20?
Multiply by 20: 0.8667 × 20 = 17.33/20. In France, this is “Très Bien” territory.
8. What happens if I miss one more question (38/45)?
38/45 equals 84.44%, which is a B (3.0 GPA). Each question on a 45-point test costs 2.22%.
9. How many questions can I miss and still get a B?
You can miss 7. The minimum for 83% is 37.35 points, so 38/45 is the lowest whole-number score that earns a B. Missing 8 gives 82.22%, a B–.
10. Can one 39/45 test change my final course grade?
Only by its weight. A test worth 10% of the course moves your final grade very little. Use a calculator to see the exact effect.
Conclusion
39 out of 45 is 86.67%, a B, and 3.0 GPA points on the standard scale, or a B+ at schools that round up. It is a good result that sits right on a grade line. Check your school’s rounding rule, review the questions you missed and plan the rest of the term to move it up.
Track every score with the easy grade calculator, and keep the full picture in mind with a clear view of how to calculate grades in class.
