Chain Size Grade 40 BBB

Width Length
Chain size Diameter
wd
Outer
ow
Inner
iw
Outer
ol
Pitch
il
mm in mm in mm in mm in mm in
1/4in 7 .0 0.274 24.4 0.960 10.4 0.410 35.3 1.390 21.5 0.845
5/16in 8.4 0.330 29.5 1.160 12.7 0.500 42.9 1.690 26.2 1.030
3/8in 10.0 0.394 35.3 1.390 15.2 0.600 51.1 2.010 31.0 1.220
7/16in 11.9 0.467 40.4 1.590 16.8    0.660 59.2    2.330 35.6    1.400
1/2in 13.0 0.510 45.5 1.790 19.6 0.770 66.3 2.610 40.4 1.590

Source: http://coxeng.co.uk/anchoring/chain/