Spanner Wrench Sizes

The "jaw size" given is the nut dimension so the spanner jaw is likely to be slightly larger.
Wrench Jaw Sizes and corresponding Nut/Bolt Use
Jaw Size
mm 		Jaw Size
Inches 		Spanner
Metric 		Spanner
AF 		Spanner
British 		Common Nut/Bolt
(*=non-preferred)
2.97 0.117     10BA  
3.20 0.126 3.2mm     M1.6
3.33 0.131     9BA  
3.86 0.152     8BA  
3.97 0.156   5/32 AF   No.0 UNC
4.00 0.157 4mm     M2
4.37 0.172     7BA  
4.76 0.188   3/16 AF   No.2 UNC
4.90 0.193     6BA  
5.00 0.197 5mm     M2.5
5.50 0.217 5.5mm     M3
5.56 0.219   7/32 AF    
5.59 0.220     5BA  
5.95 0.234   15/64 AF    
6.00 0.236 6mm     M3.5*
6.30 0.248     4BA  
6.35 0.250   1/4 AF   No.4 UNC
7.00 0.276 7mm     M4
7.14 0.281   9/32 AF    
7.16 0.282     3BA  
7.94 0.313   5/16 AF   No.6 UNC
8.00 0.315 8mm     M5
8.23 0.324     2BA  
8.59 0.338     1/8 W; 3/16 BSF  
8.73 0.344   11/32 AF   No.8 UNC
9.00 0.354 9mm      
9.27 0.365     1BA  
9.53 0.375   3/8 AF   No.10 UNC
10.00 0.394 10mm     M6
10.49 0.413     0BA  
11.00 0.433 11mm     M7*;
11.11 0.438   7/16 AF   1/4 UNF
11.30 0.445     3/16 W; 1/4 BSF  
12.00 0.472 12mm      
12.70 0.500   1/2 AF   5/16 UNF
13.00 0.512 13mm     M8
13.34 0.525     1/4 W; 5/16 BSF  
14.00 0.551 14mm      
14.29 0.563   9/16 AF   3/8 UNF
15.00 0.591 15mm      
15.24 0.600     5/16 W; 3/8 BSF  
15.88 0.625   5/8 AF   7/16 UNF (bolt)
16.00 0.630 16mm      
17.00 0.669 17mm     M10
17.46 0.688   11/16 AF   7/16 UNF (nut)
18.00 0.709 18mm      
18.03 0.710     3/8 W; 7/16 BSF  
19.00 0.748 19mm     M12
19.05 0.750   3/4 AF   1/2 UNF
20.00 0.787 20mm      
20.64 0.813   13/16 AF   9/16 UNF
20.83 0.820     7/16 W; 1/2 BSF  
21.00 0.827 21mm      
22.00 0.866 22mm     M14*
22.23 0.875   7/8 AF   9/16 UNF (nut) 
23.00 0.906 23mm      
23.37 0.920     1/2 W; 9/16 BSF  
23.81 0.938   15/16 AF   5/8 UNF
24.00 0.945 24mm     M16
25.00 0.984 25mm      
25.40 1.000   1 AF    
25.65 1.010     9/16 W; 5/8 BSF  
26.00 1.024 26mm      
26.99 1.063   1-1/16 AF    
27.00 1.063 27mm     M18*
27.94 1.100     5/8 W; 11/16 BSF  
28.00 1.102 28mm      
28.58 1.125   1-1/8 AF   3/4 UNF
30.00 1.181 30mm     M20
30.48 1.200     11/16 W; 3/4 BSF  
31.75 1.250   1-1/4 AF    
32.00 1.260 32mm     M22*
33.02 1.300     3/4 W; 7/8 BSF  
33.34 1.313   1-5/16 AF   7/8 UNF
34.00 1.339 34mm      
35.31 1.390     13/16 W?  
36.00 1.417 36mm     M24
36.51 1.438   1-7/16 AF    
37.59 1.480     7/8 W; 1 BSF  
38.00 1.496 38mm      
38.10 1.500   1-1/2 AF   1 UNF
40.13 1.580     15/16 W?  
41.00 1.614 41mm     M27*
41.28 1.625   1-5/8 AF    
42.42 1.670     1 W; 1-1/8 BSF  
42.86 1.688   1-11/16 AF   1-1/8 UNF
46.00 1.811 46mm     M30
46.04 1.813   1-13/16 AF    
47.24 1.860     1-1/8 W; 1-1/4 BSF  
47.63 1.875   1-7/8 AF   1-1/4 UNF
50.00 1.969 50mm     M33*
50.80 2.000   2 AF    
52.07 2.050     1-1/4 W; 1-3/8 BSF  
52.39 2.063   2-1/16 AF   1-3/8 UNF
55.00 2.165 55mm     M36
55.56 2.188   2-3/16 AF    
56.39 2.220     1-3/8 W; 1-1/2 BSF  
57.15 2.250   2-1/4 AF   1-1/2 UNF
60.00 2.362 60mm     M39*

Stolen from: http://www.sat.dundee.ac.uk/psc/spanner_jaw.html
Last Updated on 27-August-2014 by Paul Crawford (web links corrected, updated text about lubrication)
Copyleft (c) 2006-14 by Paul S. Crawford. All rights reserved.
Email psc(at)sat(dot)dundee(dot)ac(dot)uk