Bolt Torque Calculator
Work out bolt load and tightening torque for flange studs from stud size, material, target stress and lubricant.
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Printable Flange Bolt Torque Chart
A one-page torque chart for ASTM A193 B7 studs at 50% of yield, with three lubricant values and ASME B16.5 stud sizes. Print it or save it as a PDF.
Flange bolt torque chartASTM A193 B7 studs at 50% of yield (362 MPa / 52.5 ksi). Source: bolttorquing.com
| Stud size | Stress area (mm²) | Bolt load (kN) | Torque K 0.12 (N·m) | Torque K 0.16 (N·m) | Torque K 0.20 (N·m) | Torque K 0.16 (ft·lbf) |
|---|---|---|---|---|---|---|
| 1/2" | 92 | 33 | 50 | 67 | 84 | 50 |
| 5/8" | 146 | 53 | 101 | 134 | 168 | 99 |
| 3/4" | 216 | 78 | 178 | 238 | 297 | 175 |
| 7/8" | 298 | 108 | 288 | 384 | 480 | 283 |
| 1" | 391 | 142 | 431 | 575 | 719 | 424 |
| 1-1/8" | 510 | 185 | 633 | 844 | 1,055 | 622 |
| 1-1/4" | 645 | 234 | 890 | 1,186 | 1,483 | 875 |
| 1-3/8" | 796 | 288 | 1,207 | 1,609 | 2,012 | 1,187 |
| 1-1/2" | 963 | 348 | 1,593 | 2,124 | 2,655 | 1,567 |
| 1-5/8" | 1,148 | 416 | 2,059 | 2,746 | 3,432 | 2,025 |
| 1-3/4" | 1,342 | 486 | 2,591 | 3,455 | 4,318 | 2,548 |
| 1-7/8" | 1,555 | 563 | 3,217 | 4,289 | 5,362 | 3,164 |
| 2" | 1,787 | 647 | 3,944 | 5,258 | 6,573 | 3,878 |
| 2-1/4" | 2,297 | 831 | 5,702 | 7,603 | 9,503 | 5,607 |
| 2-1/2" | 2,865 | 1,037 | 7,902 | 10,535 | 13,169 | 7,771 |
Assumptions: B7 yield 724 MPa (105 ksi) for sizes up to 2-1/2". Torque T = K × F × D. Values are a worked example for planning, not an approved procedure: use target loads approved for your flange, gasket and bolting (see ASME PCC-1), and convert torque to pump pressure with the chart for your exact hydraulic wrench.
Stud sizes for ASME B16.5 weld neck flanges
| Pipe size | Class 150 | Class 300 |
|---|---|---|
| 2 in | 4 × 5/8" | 8 × 5/8" |
| 4 in | 8 × 5/8" | 8 × 3/4" |
| 6 in | 8 × 3/4" | 12 × 3/4" |
| 8 in | 8 × 3/4" | 12 × 7/8" |
| 10 in | 12 × 7/8" | 16 × 1" |
| 12 in | 12 × 7/8" | 16 × 1-1/8" |
This chart is the printable version of our flange bolt torque chart guide, which explains the assumptions in detail. For other materials, stress levels or metric studs, use the bolt torque calculator.