---
type: chart
title: "Bolt Torque Chart"
tables: 3
url: https://manufacturingprocesses.org/charts/bolt-torque-chart
---

# 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.

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.

## SAE inch bolts, coarse thread (UNC) — ft-lb

| Size | TPI | Stress area (in²) | Gr 2 clamp (lb) | Gr 2 dry (ft-lb) | Gr 2 lubed (ft-lb) | Gr 5 clamp (lb) | Gr 5 dry (ft-lb) | Gr 5 lubed (ft-lb) | Gr 8 clamp (lb) | Gr 8 dry (ft-lb) | Gr 8 lubed (ft-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 |

## Metric bolts, coarse thread — dry, K = 0.20 (N·m)

| Thread | Pitch (mm) | 8.8 clamp (kN) | 8.8 dry (N·m) | 10.9 clamp (kN) | 10.9 dry (N·m) | 12.9 clamp (kN) | 12.9 dry (N·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 |

## Metric bolts, coarse thread — lubricated, K = 0.15 (N·m)

| Thread | 8.8 lubed (N·m) | 10.9 lubed (N·m) | 12.9 lubed (N·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 |

## Notes

**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%.

## FAQ

### How 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.

## Sources

- [Fastenal — Torque-Tension Reference Guide (clamp loads, stress areas, T = KDF basis)](https://www.fastenal.com/content/merch_rules/images/fcom/content-library/Torque-Tension%20Reference%20Guide.pdf)
- [Portland Bolt — Bolt Torque Chart](https://www.portlandbolt.com/technical/tools/bolt-torque-chart/)

## Related processes

- [Mechanical Fastening](https://manufacturingprocesses.org/processes/joining/mechanical-fastening.md)
- [Sheet Metal Fabrication](https://manufacturingprocesses.org/processes/forming/sheet-metal-fabrication.md)

## Related charts

- [Thread Size Chart](https://manufacturingprocesses.org/charts/thread-size-chart.md)
- [Tap Drill Chart](https://manufacturingprocesses.org/charts/tap-drill-chart.md)

---

*Source: [Manufacturing Processes](https://manufacturingprocesses.org/charts/bolt-torque-chart)*

*Last updated: August 11, 2026*