Bolt Torque Chart
Torque and clamp load for SAE Grade 2, 5 and 8 inch bolts and metric class 8.8, 10.9 and 12.9 bolts, dry and lubricated, at 75% of proof load.
- Tables
- 3
- Rows
- 24
- Units
- in², lb, ft-lb, mm, kN, N·m
- References
- 2
- Revised
- 2026-08-11
SAE inch bolts, coarse thread (UNC) — ft-lb
| Size | TPI | Stress areain² | Gr 2 clamplb | Gr 2 dryft-lb | Gr 2 lubedft-lb | Gr 5 clamplb | Gr 5 dryft-lb | Gr 5 lubedft-lb | Gr 8 clamplb | Gr 8 dryft-lb | Gr 8 lubedft-lb |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/4-20 | 20 | 0.0318 | 1312 | 5.5 | 4.1 | 2029 | 8.5 | 6.3 | 2864 | 11.9 | 8.9 |
| 5/16-18 | 18 | 0.0524 | 2162 | 11.3 | 8.4 | 3342 | 17.4 | 13.1 | 4719 | 24.6 | 18.4 |
| 3/8-16 | 16 | 0.0775 | 3197 | 20 | 15 | 4940 | 30.9 | 23.2 | 6974 | 43.6 | 32.7 |
| 7/16-14 | 14 | 0.1063 | 4385 | 32 | 24 | 6777 | 49.4 | 37.1 | 9568 | 69.8 | 52.3 |
| 1/2-13 | 13 | 0.1419 | 5853 | 48.8 | 36.6 | 9046 | 75.4 | 56.5 | 12771 | 106.4 | 79.8 |
| 9/16-12 | 12 | 0.182 | 7508 | 70.4 | 52.8 | 11599 | 108.7 | 81.6 | 16375 | 153.5 | 115.1 |
| 5/8-11 | 11 | 0.226 | 9322 | 97.1 | 72.8 | 14408 | 150.1 | 112.6 | 20340 | 211.9 | 158.9 |
| 3/4-10 | 10 | 0.3345 | 13798 | 172.5 | 129.4 | 21322 | 266.5 | 199.9 | 30101 | 376.3 | 282.2 |
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8 rows × 12 columnsUnits: in², lb, ft-lb
Metric bolts, coarse thread — dry, K = 0.20 (N·m)
| Thread | Pitchmm | 8.8 clampkN | 8.8 dryN·m | 10.9 clampkN | 10.9 dryN·m | 12.9 clampkN | 12.9 dryN·m |
|---|---|---|---|---|---|---|---|
| M6x1 | 1 | 8.8 | 10.5 | 12.5 | 15 | 14.6 | 17.6 |
| M8x1.25 | 1.25 | 15.9 | 25.5 | 22.8 | 36.5 | 26.6 | 42.6 |
| M10x1.5 | 1.5 | 25.2 | 50.5 | 36.1 | 72.2 | 42.2 | 84.4 |
| M12x1.75 | 1.75 | 36.7 | 88 | 52.5 | 125.9 | 61.3 | 147.1 |
| M14x2 | 2 | 50.2 | 140.6 | 71.9 | 201.2 | 84 | 235.1 |
| M16x2 | 2 | 68.1 | 218.1 | 97.5 | 312.1 | 114 | 364.7 |
| M18x2.5 | 2.5 | 83.7 | 301.4 | 119.8 | 431.3 | 140 | 504.1 |
| M20x2.5 | 2.5 | 106.5 | 425.9 | 152.4 | 609.5 | 178.1 | 712.3 |
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8 rows × 8 columnsUnits: mm, kN, N·m
Basis and references
Every value on this page is computed from the standard short-form relationship T = K · D · F, where T is torque, K is the nut factor (a dimensionless friction coefficient), D is nominal bolt diameter and F is the target clamp load.
The assumptions behind the numbers, which you must read before using them: target clamp load is 75% of proof load, the standard industry basis for reusable joints. K = 0.20 dry (plain or zinc-plated) and K = 0.15 lubricated (oil, wax or tapping fluid); cadmium and PTFE coatings run nearer 0.12 and are not tabulated. The joint is assumed non-gasketed, metal-to-metal and rigid, with a hardened washer under the turned element, and the nut or tapped hole is assumed at least as strong as the bolt. Proof loads used are Grade 2 = 55,000 psi, Grade 5 = 85,000 psi and Grade 8 = 120,000 psi.
Torque is an indirect proxy for tension, and K scatters by roughly ±25% even under controlled conditions. Treat these as estimates, not specifications.
References
- [1]Fastenal — Torque-Tension Reference Guide (clamp loads, stress areas, T = KDF basis)
- [2]Portland Bolt — Bolt Torque Chart
Every value on this page was set against at least two of these sources and recomputed rather than transcribed. Where they disagree, the disagreement is recorded in the notes below.
Metric bolts, coarse thread — lubricated, K = 0.15 (N·m)
| Thread | 8.8 lubedN·m | 10.9 lubedN·m | 12.9 lubedN·m |
|---|---|---|---|
| M6x1 | 7.9 | 11.3 | 13.2 |
| M8x1.25 | 19.1 | 27.3 | 32 |
| M10x1.5 | 37.8 | 54.1 | 63.3 |
| M12x1.75 | 66 | 94.4 | 110.3 |
| M14x2 | 105.5 | 150.9 | 176.4 |
| M16x2 | 163.6 | 234.1 | 273.5 |
| M18x2.5 | 226.1 | 323.5 | 378 |
| M20x2.5 | 319.4 | 457.1 | 534.2 |
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8 rows × 4 columnsUnits: N·m
Revision and twin
Last reviewed . This page carries 24 rows across 3 tables, all of them in the HTML — nothing is paginated, gated or fetched.
Plain-Markdown twin: /charts/bolt-torque-chart.md
Notes to the tables
6 notesWhere this data disagrees with itself, with other published charts, or with what the number looks like it means.
Do not use this chart for structural steel connections (use RCSC/AISC), flanged pressure joints (use ASME PCC-1) or wheel fasteners (use the OEM spec). For anything safety-critical, control tension directly: turn-of-nut, bolt stretch, ultrasonic measurement or load-indicating washers.
Many shop charts list Grade 2 1/2-13 dry at about 55 ft-lb; this chart gives 48.8. The difference is the clamp-load basis — those charts typically assume 85% of proof load, or a 57,000 psi proof value. Neither is wrong, but the two bases must never be mixed inside one joint analysis. The conservative 75%-of-proof basis is used here for consistency across all three grades.
Grade 2 is excluded above 3/4 in on purpose. SAE J429 Grade 2 proof load drops from 55,000 psi to 33,000 psi above 3/4 in, so extrapolating the table would produce dangerously high values.
A third-source metric spot-check gives M10 dry as 48 / 68 / 80 N·m for 8.8 / 10.9 / 12.9 against this chart's 50 / 72 / 84 — a roughly 5% gap caused by a different clamp-load basis (some charts use 70% of proof, or 65% of yield). Both are defensible; the basis here is stated explicitly.
Small sizes are usually specified in inch-pounds in the field. Multiply the ft-lb value by 12: 1/4-20 Grade 5 dry is 101 in-lb, Grade 8 dry is 143 in-lb.
Clamp loads were independently re-derived as 0.75 × proof × tensile stress area and agreed with the published Fastenal values to within 0.1%.
Questions
7 questionsHow much torque for a 1/2-13 Grade 8 bolt?
106.4 ft-lb dry and 79.8 ft-lb lubricated, at a clamp load of 12,771 lb (75% of proof). Grade 5 at the same size is 75.4 ft-lb dry, and Grade 2 is 48.8 ft-lb dry.
How much torque for an M10 class 8.8 bolt?
50 N·m dry and 38 N·m lubricated, at a clamp load of 25.2 kN. Class 10.9 is 72 N·m dry and class 12.9 is 84 N·m dry.
Why is lubricated torque lower than dry torque?
Because lubrication lowers the nut factor K from about 0.20 to about 0.15, so less of the applied torque is lost to friction and more of it becomes bolt tension. Applying the dry figure to a lubricated bolt over-tensions it by roughly a third and can yield the fastener.
What does T = K · D · F mean?
Torque equals the nut factor times the nominal bolt diameter times the target clamp load. K bundles all the friction in the joint — thread friction and under-head friction — into one empirical number, which is why torque is only ever an indirect proxy for the tension you actually want.
How accurate are torque charts?
K scatters by roughly ±25% even under controlled laboratory conditions, so the clamp load you actually achieve varies by about the same amount. Where preload matters, measure it directly with turn-of-nut, bolt stretch, ultrasonic measurement or load-indicating washers.
Why are there no Grade 2 values above 3/4 inch?
SAE J429 Grade 2 proof strength drops from 55,000 psi to 33,000 psi above 3/4 in. Extending the table with the 55,000 psi basis would produce torque values well above what the fastener can carry.
Can I use these numbers for structural steel or wheel bolts?
No. Structural steel connections follow RCSC/AISC, flanged pressure joints follow ASME PCC-1, and wheel fasteners follow the vehicle manufacturer's specification. This chart is for general non-gasketed metal-to-metal joints.
How to cite this page
Manufacturing Processes. “Bolt Torque Chart.” manufacturingprocesses.org, last reviewed 2026-08-11. https://manufacturingprocesses.org/charts/bolt-torque-chart
If you reproduce a table, cite the standard it derives from as well — the references are the primary sources, this page is a cross-checked transcription of them.