Unified Screw Threads – Course are the most common type of thread found in the US. Unified screw threads consist of a 60-degree thread profile.
The table below shows the major and minor diameters, thread pitch (given in threads per inch, tpi) and finally the diameter area which is necessary for bolt tensile strength calculations.
| Size | Major Dia | Threads Per Inch | Pitch Dia | Minor Dia External | Minor Dia Internal | Minor Dia Area | Tensile Stress Area |
| # | inch | tpi | inch | inch | inch | sq. inch | sq. inch |
| #1 | 0.073 | 64 | 0.0629 | 0.0544 | 0.0561 | 0.00218 | 0.00263 |
| #2 | 0.086 | 56 | 0.0744 | 0.0648 | 0.0667 | 0.0031 | 0.0037 |
| #3 | 0.099 | 48 | 0.0855 | 0.0741 | 0.0764 | 0.00406 | 0.00487 |
| #4 | 0.112 | 40 | 0.0958 | 0.0822 | 0.0849 | 0.00496 | 0.00604 |
| #5 | 0.125 | 40 | 0.1088 | 0.0952 | 0.0979 | 0.00672 | 0.00796 |
| #6 | 0.138 | 32 | 0.1177 | 0.1008 | 0.1042 | 0.00745 | 0.00909 |
| #8 | 0.164 | 32 | 0.1437 | 0.1268 | 0.1302 | 0.01196 | 0.014 |
| #10 | 0.19 | 24 | 0.1629 | 0.1404 | 0.1449 | 0.0145 | 0.0175 |
| #12 | 0.216 | 24 | 0.1889 | 0.1664 | 0.1709 | 0.0206 | 0.0242 |
| ¼ | 0.25 | 20 | 0.2175 | 0.1905 | 0.1959 | 0.0269 | 0.0318 |
| 5/16 | 0.3125 | 18 | 0.2764 | 0.2464 | 0.2524 | 0.0454 | 0.0524 |
| 3/8 | 0.375 | 16 | 0.3344 | 0.3005 | 0.3073 | 0.0678 | 0.0775 |
| 7/16 | 0.4375 | 14 | 0.3911 | 0.3525 | 0.3602 | 0.0933 | 0.1063 |
| ½ | 0.5 | 13 | 0.45 | 0.4084 | 0.4167 | 0.1257 | 0.1419 |
| 9/16 | 0.5625 | 12 | 0.5084 | 0.4633 | 0.4723 | 0.162 | 0.182 |
| 5/8 | 0.625 | 11 | 0.566 | 0.5168 | 0.5266 | 0.202 | 0.226 |
| ¾ | 0.75 | 10 | 0.685 | 0.6309 | 0.6417 | 0.302 | 0.334 |
| 7/8 | 0.875 | 9 | 0.8028 | 0.7427 | 0.7547 | 0.419 | 0.462 |
| 1 | 1 | 8 | 0.9188 | 0.8512 | 0.8647 | 0.551 | 0.606 |
| 1-1/8 | 1.125 | 7 | 1.0322 | 0.9549 | 0.9704 | 0.693 | 0.763 |
| 1¼ | 1.25 | 7 | 1.1572 | 1.0799 | 1.0954 | 0.89 | 0.969 |
| 1-3/8 | 1.375 | 6 | 1.2667 | 1.1766 | 1.1946 | 1.054 | 1.155 |
| 1½ | 1.5 | 6 | 1.3917 | 1.3016 | 1.3196 | 1.294 | 1.405 |
| 1¾ | 1.75 | 5 | 1.6201 | 1.5119 | 1.5335 | 1.74 | 1.9 |
| 2 | 2 | 4.5 | 1.8557 | 1.7353 | 1.7594 | 2.3 | 2.5 |
| 2¼ | 2.25 | 4.5 | 2.1057 | 1.9853 | 2.0094 | 3.02 | 3.25 |
| 2½ | 2.5 | 4 | 2.3376 | 2.2023 | 2.2294 | 3.72 | 4 |
| 2¾ | 2.75 | 4 | 2.5876 | 2.4523 | 2.4794 | 4.62 | 4.93 |
| 3 | 3 | 4 | 2.8376 | 2.7023 | 2.7294 | 5.62 | 5.97 |
| 3¼ | 3.25 | 4 | 3.0876 | 2.9523 | 2.9794 | 6.72 | 7.1 |
| 3½ | 3.5 | 4 | 3.3376 | 3.2023 | 3.2294 | 7.92 | 8.33 |
| 3¾ | 3.75 | 4 | 3.5876 | 3.4523 | 3.4794 | 9.21 | 9.66 |
| 4 | 4 | 4 | 3.8376 | 3.7023 | 3.7294 | 10.61 | 11.08 |
If you need to apply more tensile load with less torque, consider using a Unified Screw Thread – Fine (UNF) instead of the Unified Screw Thread – Course (UNC).