Unified Thread Size Charts

The Unified Thread Standard (UTS) defines a standard thread form and series—along with allowances, tolerances, and designations—for screw threads commonly used in the United States and Canada.

It is the main standard for bolts, nuts, and a wide variety of other used in these countries. It has the same 60° profile as the ISO metric screw thread, but the characteristic dimensions of each UTS thread (outer diameter and pitch) were chosen as an fraction rather than a millimeter value. The UTS is currently controlled by ASME/ANSI in the United States.

UNC - Unified Coarse Thread

Size Diameter TPS Pitch Diameter Male Minor Diameter Female Minor Diameter
#1 0.0730 64 0.0629 0.0544 0.0561
#2 0.0860 56 0.0744 0.0648 0.0667
#3 0.0990 48 0.0855 0.0741 0.0764
#4 0.1120 40 0.0958 0.0822 0.0849
#5 0.1250 40 0.1088 0.0952 0.0979
#6 0.1380 32 0.1177 0.1008 0.1042
#7 0.1640 32 0.1437 0.1268 0.1302
#10 0.1900 24 0.1629 0.1404 0.1449
#12 0.2160 24 0.1889 0.1664 0.1709
1/4" 0.2500 20 0.2175 0.1905 0.1959
5/16" 0.3125 18 0.2764 0.2464 0.2524
3/8" 0.3750 16 0.3344 0.3005 0.3073
7/16" 0.4375 14 0.3911 0.3525 0.3602
1/2" 0.5000 13 0.4500 0.4084 0.4167
9/16" 0.5625 12 0.5084 0.4633 0.4723
5/8" 0.6250 11 0.5660 0.5168 0.5266
3/4" 0.7500 10 0.6850 0.6309 0.6417
7/8" 0.8750 9 0.8028 0.7427 0.7547
1" 1.0000 8 0.9188 0.8512 0.8647

UNC - Unified Coarse Thread

Size Diameter TPS Pitch Diameter Male Minor Diameter Female Minor Diameter
#0 0.0600 80 0.0519 0.0451 0.0465
#1 0.0730 72 0.0640 0.0565 0.0580
#2 0.0860 64 0.0759 0.0674 0.0691
#3 0.0990 56 0.0874 0.0778 0.0797
#4 0.1120 48 0.0985 0.0871 0.0894
#5 0.1250 44 0.1102 0.0979 0.1004
#6 0.1380 40 0.1218 0.1082 0.1109
#8 0.1640 36 0.1460 0.1309 0.1339
#10 0.1900 32 0.1697 0.1528 0.1562
#12 0.2160 28 0.1928 0.1734 0.1773
1/4" 0.2500 28 0.2268 0.2074 0.2113
5/16" 0.3125 24 0.2854 0.2629 0.2674
3/8" 0.3750 24 0.3479 0.3254 0.3299
7/16" 0.4375 20 0.4050 0.3780 0.3834
1/2" 0.5000 20 0.4675 0.4405 0.4459
9/16" 0.5625 18 0.5264 0.4964 0.5024
5/8" 0.6250 18 0.5889 0.5589 0.5649
3/4" 0.7500 16 0.7094 0.6763 0.6823
7/8" 0.8750 14 0.8286 0.7900 0.7977
1" 1.0000 12 0.9459 0.9001 0.9098

Metric Thread Conversion

Metric Coarse Metric Fine UNC UNF
M2 x 0.4 - 1-64 1-72
M2.5 x 0.45 - 3-48 3-56
M3 x 0.5 - 4-40 4-48
M3.5 x 0.6 - 6-32 6-40
M4 x 0.7 - 8-32 8-36
M5 x 0.8 - 10-24 10-32
M6 x 1 M6 x 0.75 1/4-20 1/4-28
M8 x 1.25 M8 x 1 5/16-18 5/16-24
M10 x 1.5 M10 x 1.25 3/8-16 3/8-24
M12 x 1.75 M12 x 1.25 1/2-13 1/2-20
M14 x 2 M14 x 1.5 9/16-12 9/16-18
M16 x 2 M16 x 1.5 5/8-11 5/8-18
M20 x 2.5 M20 x 1.5 3/4-10 3/4-16
M24 x 3 M24 x 2 1-8 1-12
M30 x 3.5 M30 x 2 1 1/4-7 1 1/8-12
M36 x 4 M36 x 3 1 1/2-6 1 1/4-12
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