US STD um Standard ASTM EQUIV 125000 µm 125mm 5 in 112000 µm       106 mm 4.24 in 100000 µm 100 mm 4 in 90000 µm 90 mm 3.5 in 80000 µm       75 mm 3 in 71000 µm     63000 µm 63 mm 2.5 in   53 mm 2.12 in 56000 µm     50000 µm 50 mm 2 in 45000 µm 45 mm 1.75 in 37500 µm 37.5 mm 1.5 in 31500 µm 31.5 mm 1.25 in 28000 µm     26500 µm 26.5 mm 1.06 in 25000 µm 25 mm 1 in 22400 µm 22.4 mm 7/8 in 20000 µm     19000 µm 19.0 mm 3/4 in 18000 µm     16000 µm 16.0 mm 5/8 in 14000 µm     13200 µm 13.2 mm 0.530 in 12500 µm 12.5 mm 1/2 in 11200 µm 11.2 mm 7/16 in 10000 µm     9500 µm 9.5 mm 3/8 in 9000 µm     8000 µm 8.0 mm 5/16 in 7100 µm     6700 µm 6.7 mm 0.265 in 6300 µm 6.3 mm 1/4 in 5600 µm 5.6 mm No.3 1/2 5000 µm     4750 µm 4.75 mm No.4 4500 µm     4000 µm 4.00 mm No.5 3550 µm     3350 µm 3.35 mm No.6 3150 µm     2800 µm 2.80 mm No.7 2500 µm     2360 µm 2.36 mm No.8 2240 µm     2000 µm 2.00 mm No.10 1800 µm     1700 µm 1.70 mm No.12 1600 µm     1400 µm 1.40 mm No.14 1250 µm     1180 µm 1.18 mm No.16 1120 µm     1000 µm 1.00 mm No.18 900 µm     850 µm 850 µm No.20 800 µm     710 µm 710 µm No.25 630 µm     600 µm 600 µm No.30 560 µm     500 µm 500 µm No.35 500 µm     425 µm 425 µm No.40 400 µm     355 µm 355 µm No.45 315 µm     300 µm 300 µm No.50 280 µm     250 µm 250 µm No.60 224 µm     212 µm 212 µm No.70 200 µm     180 µm 180 µm No.80 160 µm     150 µm 150 µm No.100 140 µm     125 µm 125 µm No.120 112 µm     106 µm 106µm No.140 100 µm     90 µm 90 µm No.170 80 µm     75 µm 75 µm No.200 71 µm     63 µm 63µm No.230 56 µm     53 µm 53 µm No.270 50 µm     45 µm 45 µm No.325 40 µm     38 µm 38 µm No.400 36 µm     32 µm   No. 450 25 µm   No. 500  20 µm   No. 635