13 out of 21 as a percentage is 61.9% (D)

A 13/21 is 61.9%, which is a D on the standard grading scale (a D− with plus and minus grades). That is a 1.0 GPA, and you got 8 wrong.

Next grade2 more → C15 out of 21 is 71.43%

With a 5-point curve66.9% → Dif your teacher adds 5 points

To pass (60%)Passed13 out of 21 is the passing line

What a 13/21 grade means

13 correct and 8 wrong on a 21-question test.
Each question is worth 4.76%, so every wrong answer costs 4.76 percentage points.
Any score from 13 to 14 out of 21 is a D.
2 more correct (15 out of 21, 71.43%) would make it a C.
It passes a 60% passing score, which needs 13 out of 21.

Divide the score by the total: 13 ÷ 21 = 0.619.
Multiply by 100: 0.619 × 100 = 61.9%.
Find 61.9% on the grading scale: A is 90% and up, B 80%, C 70% and D 60%, so it is a D.

Rounded to a whole number this is 62%, and the letter grade stays the same.

Scale	Cutoffs	Letter	GPA
Standard A–F	A 90, B 80, C 70, D 60	D	1.0
Plus and minus	A 93, A− 90, B+ 87, B 83, B− 80 …	D−	0.7
7-point	A 93, B 85, C 77, D 70	F	0.0

Which scale applies depends on your school or teacher; the syllabus usually says. The grading scales guide compares them.

Every possible score out of 21, with 13 highlighted. Pick any score to see its page.

Correct	Wrong	Percentage	Grade
21	0	100%	A
20	1	95.2%	A
19	2	90.5%	A
18	3	85.7%	B
17	4	81%	B
16	5	76.2%	C
15	6	71.4%	C
14	7	66.7%	D
13	8	61.9%	D
12	9	57.1%	F
11	10	52.4%	F
10	11	47.6%	F
9	12	42.9%	F
8	13	38.1%	F
7	14	33.3%	F
6	15	28.6%	F
5	16	23.8%	F
4	17	19%	F
3	18	14.3%	F
2	19	9.5%	F
1	20	4.8%	F
0	21	0%	F

It is a D. Most US schools count 60% or more as passing, but it is below average. On a stricter 7-point scale it would be an F.

1.0 on a 4.0 scale as a D, or 0.7 if your school uses plus and minus grades (D−).

With a half point, 13.5 out of 21 is 64.29%: a D on the standard scale and a D with plus and minus grades.

8 at most with a 60% passing score: you need 13 out of 21. With a 70% passing score you need 15 out of 21.