Fractions to Percent

Quick reference for common exam fractions and their percentage values, plus important square roots used in approximation.

Mental rules: 1/x ≈ (100 ÷ x)% • p% = p/100 (then simplify the fraction).

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Fraction % value Fraction % value
1 100% 1/8 12.5%
1/2 50% 1/9 11.11%
1/3 33.33% 1/10 10%
1/4 25% 1/11 ≈ 9.09%
1/5 20% 1/12 ≈ 8.33%
1/6 16.66% 1/13 ≈ 7.69%
1/7 ≈ 14.28% 1/14 ≈ 7.14%
2/3 66.66% 3/4 75%
1/20 5% 1/25 4%
3/5 60% 2/5 40%
2/4 50% 3/10 30%
4/5 80% 7/10 70%
5/6 83.33% 5/8 62.5%
3/6 50% 7/8 87.5%
2/8 25% 5/9 55.55%
4/8 50% 8/9 88.88%
6/8 75% 9/10 90%
7/10 70% 11/12 ≈ 91.66%
9/10 90% 13/14 ≈ 92.85%
19/20 95% 24/25 96%
17/20 85% 21/25 84%
13/20 65% 16/25 64%
11/20 55% 9/25 36%
3/20 15% 4/25 16%
7/20 35% 6/25 24%
Fraction % value Fraction % value
2/7 ≈ 28.57% 3/7 ≈ 42.85%
4/7 ≈ 57.14% 5/7 ≈ 71.42%
6/7 ≈ 85.71% 3/8 37.5%
5/8 62.5% 7/8 87.5%
1/16 6.25% 3/16 18.75%
5/16 31.25% 7/16 43.75%
9/16 56.25% 11/16 68.75%
13/16 81.25% 15/16 93.75%
2/9 22.22% 4/9 44.44%
5/9 55.55% 7/9 77.77%
8/9 88.88% 2/11 ≈ 18.18%
3/11 ≈ 27.27% 4/11 ≈ 36.36%
5/11 ≈ 45.45% 6/11 ≈ 54.54%
7/11 ≈ 63.63% 8/11 ≈ 72.72%
9/11 ≈ 81.81% 10/11 ≈ 90.90%
2/12 16.66% 3/12 25%
4/12 33.33% 6/12 50%
8/12 66.66% 9/12 75%
10/12 83.33% 11/12 ≈ 91.66%
2/13 ≈ 15.38% 3/13 ≈ 23.07%
4/13 ≈ 30.76% 5/13 ≈ 38.46%
6/13 ≈ 46.15% 7/13 ≈ 53.84%
8/13 ≈ 61.53% 9/13 ≈ 69.23%
10/13 ≈ 76.92% 11/13 ≈ 84.61%
12/13 ≈ 92.30% 2/14 ≈ 14.28%
3/14 ≈ 21.42% 4/14 ≈ 28.57%
5/14 ≈ 35.71% 6/14 ≈ 42.85%
8/14 ≈ 57.14% 9/14 ≈ 64.28%
10/14 ≈ 71.42% 11/14 ≈ 78.57%
12/14 ≈ 85.71% 13/14 ≈ 92.85%
2/15 ≈ 13.33% 4/15 ≈ 26.66%
7/15 ≈ 46.66% 8/15 ≈ 53.33%
11/15 ≈ 73.33% 13/15 ≈ 86.66%
14/15 ≈ 93.33% 2/16 12.5%
4/16 25% 6/16 37.5%
8/16 50% 10/16 62.5%
12/16 75% 14/16 87.5%
Denominator Fractions % values
2 1/2 50%
3 1/3, 2/3 33.33%, 66.66%
4 1/4, 2/4, 3/4 25%, 50%, 75%
5 1/5, 2/5, 3/5, 4/5 20%, 40%, 60%, 80%
6 1/6, 5/6 16.66%, 83.33%
7 1/7, 2/7, 3/7, 4/7, 5/7, 6/7 ≈14.28%, 28.57%, 42.85%, 57.14%, 71.42%, 85.71%
8 1/8, 3/8, 5/8, 7/8 12.5%, 37.5%, 62.5%, 87.5%
9 1/9, 2/9, 4/9, 5/9, 7/9, 8/9 11.11%, 22.22%, 44.44%, 55.55%, 77.77%, 88.88%
10 1/10, 3/10, 7/10, 9/10 10%, 30%, 70%, 90%
11 1/11, 2/11, 3/11, ..., 10/11 ≈9.09%, 18.18%, 27.27%, ..., 90.90%
12 1/12, 5/12, 7/12, 11/12 ≈8.33%, 41.66%, 58.33%, 91.66%
13 1/13, 2/13, 3/13, ..., 12/13 ≈7.69%, 15.38%, 23.07%, ..., 92.30%
14 1/14, 3/14, 5/14, 9/14, 11/14, 13/14 ≈7.14%, 21.42%, 35.71%, 64.28%, 78.57%, 92.85%
15 1/15, 2/15, 4/15, 7/15, 8/15, 11/15, 13/15, 14/15 ≈6.66%, 13.33%, 26.66%, 46.66%, 53.33%, 73.33%, 86.66%, 93.33%
16 1/16, 3/16, 5/16, 7/16, 9/16, 15/16 6.25%, 18.75%, 31.25%, 43.75%, 56.25%, 93.75%
17 1/17, 2/17, 3/17, ..., 16/17 ≈5.88%, 11.76%, 17.64%, ..., 94.11%
18 1/18, 5/18, 7/18, 11/18, 13/18, 17/18 ≈5.55%, 27.77%, 38.88%, 61.11%, 72.22%, 94.44%
19 1/19, 2/19, 3/19, ..., 18/19 ≈5.26%, 10.52%, 15.78%, ..., 94.73%
20 1/20, 3/20, 7/20, 9/20, 11/20, 13/20, 17/20, 19/20 5%, 15%, 35%, 45%, 55%, 65%, 85%, 95%
21 1/21, 2/21, 4/21, 5/21, 8/21, 10/21, 11/21, 13/21, 16/21, 17/21, 19/21, 20/21 ≈4.76%, 9.52%, 19.04%, 23.80%, 38.09%, 47.61%, 52.38%, 61.90%, 76.19%, 80.95%, 90.47%, 95.23%
22 1/22, 3/22, 5/22, 7/22, 9/22, 13/22, 15/22, 17/22, 19/22, 21/22 ≈4.54%, 13.63%, 22.72%, 31.81%, 40.90%, 59.09%, 68.18%, 77.27%, 86.36%, 95.45%
23 1/23, 2/23, 3/23, ..., 22/23 ≈4.34%, 8.69%, 13.04%, ..., 95.65%
24 1/24, 5/24, 7/24, 11/24, 13/24, 17/24, 19/24, 23/24 ≈4.16%, 20.83%, 29.16%, 45.83%, 54.16%, 70.83%, 79.16%, 95.83%
25 1/25, 2/25, 3/25, ..., 24/25 4%, 8%, 12%, ..., 96%
n √n (approx) n √n (approx)
1 1.000 9 3.000
2 1.414 10 3.162
3 1.732 11 3.317
4 2.000 12 3.464
5 2.236 13 3.606
6 2.449 14 3.742
7 2.646 15 3.873
8 2.828 16 4.000
17 4.123 18 4.242
19 4.358 20 4.472
21 4.582 22 4.690
23 4.795 24 4.898
25 5.000 26 5.099
27 5.196 28 5.291
29 5.385 30 5.477
31 5.567 32 5.656
33 5.744 34 5.831
35 5.916 36 6.000
37 6.082 38 6.164
39 6.244 40 6.324
41 6.403 42 6.480
43 6.557 44 6.633
45 6.708 46 6.782
47 6.855 48 6.928
49 7.000 50 7.071
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