There are many shoe size systems in the world - French, English, U.S., Japanese, Chinese etc. and you most use the one associated with where you live.
Each size system has their own size description such as French in numbers like 35, 36, 37, 38 etc for women's sizes seldom with half size while U.S. in single numbers like 5, 5 1/2, 6 etc. with half sizes.
Men’s
|
US |
8 |
8.5 |
9 |
9.5 |
10 |
10.5 |
11 |
12 |
13 |
|
CM |
26 |
26.5 |
27 |
27.5 |
28 |
28.5 |
29 |
30 |
31 |
|
EUR |
40.5 |
41 |
42 |
42.5 |
43 |
44 |
44.5 |
46 |
47 |
|
UK |
7 |
7.5 |
8 |
8.5 |
9 |
9.5 |
10 |
11 |
12 |
Women’s
|
US |
5 |
5.5 |
6 |
6.5 |
7 |
7.5 |
8 |
8.5 |
9 |
9.5 |
10 |
11 |
|
CM |
21.5 |
22 |
22.5 |
23 |
23.5 |
24 |
24.5 |
25 |
25.5 |
26 |
26.5 |
27.5 |
|
EUR |
34.5 |
35 |
36 |
36.5 |
37 |
38 |
38.5 |
39 |
40 |
40.5 |
41 |
42.5 |
|
UK |
2.5 |
3 |
3.5 |
4 |
4.5 |
5 |
5.5 |
6 |
6.5 |
7 |
7.5 |
8.5 |
Boy’s
|
US |
11 |
11.5 |
12 |
12.5 |
13 |
13.5 |
1 |
1.5 |
2 |
2.5 |
3 |
4 |
5 |
6 |
7 |
|
CM |
16 |
16.5 |
17 |
17.5 |
18 |
18.5 |
19 |
19.5 |
20 |
20.5 |
21 |
22 |
23 |
24 |
25 |
|
EUR |
27.5 |
28 |
29 |
30 |
30.5 |
31 |
31.5 |
32 |
32.5 |
33 |
34 |
35 |
36.5 |
38 |
39 |
|
UK |
10.5 |
11 |
11.5 |
12 |
12.5 |
13 |
13.5 |
1 |
1.5 |
2 |
2.5 |
3 |
4 |
5 |
6 |
Girl’s
|
US |
11 |
11.5 |
12 |
12.5 |
13 |
13.5 |
1 |
1.5 |
2 |
2.5 |
3 |
4 |
|
CM |
16 |
16.5 |
17 |
17.5 |
18 |
18.5 |
19 |
19.5 |
20 |
20.5 |
21 |
22 |
|
EUR |
27.5 |
28 |
29 |
30 |
30.5 |
31 |
31.5 |
32 |
32.5 |
33 |
34 |
35 |
|
UK |
10.5 |
11 |
11.5 |
12 |
12.5 |
13 |
13.5 |
1 |
1.5 |
2 |
2.5 |
3 |
Toddler’s
|
US |
5 |
5.5 |
6 |
6.5 |
7 |
7.5 |
8 |
8.5 |
9 |
10 |
|
CM |
10 |
10.5 |
11 |
11.5 |
12 |
12.5 |
13 |
13.5 |
14 |
15 |
|
EUR |
21 |
21.5 |
22 |
22.5 |
23.5 |
24 |
24.5 |
25 |
25.5 |
26.5 |
|
UK |
4.5 |
5 |
5.5 |
6 |
6.5 |
7 |
7.5 |
8 |
8.5 |
9.5 |
The grading rule of the difference between sizes are quite different, for example the French grading difference is about 4.20 mm and the U.S. grading difference between sizes is 8.46 mm or 5/16" and 5 mm or 3/16" in half size.
To have your foot perfect size fit you need to measure your actual foot length then to check with the brand's actual size in length as you cannot figure out the answer from the different size system charts.