Bolt Torque Specification Chart
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Complete torque specs by bolt size for SAE and Metric fasteners. Find the right tightening values for Grade 2, 5, 8 and Class 8.8, 10.9, 12.9 bolts.
Photo via Unsplash
Complete torque specs by bolt size for SAE and Metric fasteners. Find the right tightening values for Grade 2, 5, 8 and Class 8.8, 10.9, 12.9 bolts.
Bolt torque depends on size, thread, and grade. A common 1/2"-13 (coarse) bolt takes about 37 ft-lbs dry in Grade 2, 75 ft-lbs in Grade 5, and 105 ft-lbs in Grade 8. SAE fasteners use grades 2, 5, and 8 (marked by 0, 3, or 6 radial lines), while metric bolts use classes 8.8, 10.9, and 12.9 — for example, an M10 coarse bolt takes ~48 Nm (8.8), 68 Nm (10.9), and 80 Nm (12.9) dry. Lubricated values run roughly 25% lower; see the chart below for every size in both ft-lbs and Nm.
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Torque values for SAE/USS (Unified National) bolts. Grade indicated by head markings: Grade 2 (no marks), Grade 5 (3 lines), Grade 8 (6 lines). Bolt grades and their strength properties are defined by the SAE J429 standard; the values below are typical published estimates for clean steel fasteners at roughly 75% of proof load. Always use the equipment manufacturer's spec when one is given. To apply these values you will need the correct driver for each bolt head, so check our socket size chart and wrench size chart.
| Bolt Size | TPI | Grade 2 | Grade 5 | Grade 8 | |||
|---|---|---|---|---|---|---|---|
| Dry | Lub | Dry | Lub | Dry | Lub | ||
| 1/4" | 20 (Coarse) | 4 ft-lbs | 3 ft-lbs | 8 ft-lbs | 6 ft-lbs | 12 ft-lbs | 9 ft-lbs |
| 5/16" | 18 (Coarse) | 8 ft-lbs | 6 ft-lbs | 17 ft-lbs | 13 ft-lbs | 24 ft-lbs | 18 ft-lbs |
| 3/8" | 16 (Coarse) | 15 ft-lbs | 11 ft-lbs | 31 ft-lbs | 23 ft-lbs | 44 ft-lbs | 33 ft-lbs |
| 7/16" | 14 (Coarse) | 24 ft-lbs | 18 ft-lbs | 49 ft-lbs | 37 ft-lbs | 70 ft-lbs | 52 ft-lbs |
| 1/2" | 13 (Coarse) | 37 ft-lbs | 28 ft-lbs | 75 ft-lbs | 56 ft-lbs | 105 ft-lbs | 79 ft-lbs |
| 9/16" | 12 (Coarse) | 53 ft-lbs | 40 ft-lbs | 110 ft-lbs | 82 ft-lbs | 155 ft-lbs | 116 ft-lbs |
| 5/8" | 11 (Coarse) | 74 ft-lbs | 56 ft-lbs | 150 ft-lbs | 112 ft-lbs | 210 ft-lbs | 158 ft-lbs |
| 3/4" | 10 (Coarse) | 120 ft-lbs | 90 ft-lbs | 260 ft-lbs | 195 ft-lbs | 375 ft-lbs | 281 ft-lbs |
| 7/8" | 9 (Coarse) | 190 ft-lbs | 142 ft-lbs | 430 ft-lbs | 322 ft-lbs | 605 ft-lbs | 454 ft-lbs |
| 1" | 8 (Coarse) | 290 ft-lbs | 218 ft-lbs | 640 ft-lbs | 480 ft-lbs | 910 ft-lbs | 682 ft-lbs |
| 1/4" | 28 (Fine) | 5 ft-lbs | 4 ft-lbs | 10 ft-lbs | 7 ft-lbs | 14 ft-lbs | 10 ft-lbs |
| 5/16" | 24 (Fine) | 10 ft-lbs | 7 ft-lbs | 19 ft-lbs | 14 ft-lbs | 27 ft-lbs | 20 ft-lbs |
| 3/8" | 24 (Fine) | 17 ft-lbs | 13 ft-lbs | 35 ft-lbs | 26 ft-lbs | 49 ft-lbs | 37 ft-lbs |
| 7/16" | 20 (Fine) | 27 ft-lbs | 20 ft-lbs | 55 ft-lbs | 41 ft-lbs | 78 ft-lbs | 58 ft-lbs |
| 1/2" | 20 (Fine) | 41 ft-lbs | 31 ft-lbs | 85 ft-lbs | 64 ft-lbs | 120 ft-lbs | 90 ft-lbs |
| 9/16" | 18 (Fine) | 59 ft-lbs | 44 ft-lbs | 120 ft-lbs | 90 ft-lbs | 170 ft-lbs | 128 ft-lbs |
| 5/8" | 18 (Fine) | 83 ft-lbs | 62 ft-lbs | 170 ft-lbs | 127 ft-lbs | 240 ft-lbs | 180 ft-lbs |
| 3/4" | 16 (Fine) | 140 ft-lbs | 105 ft-lbs | 295 ft-lbs | 221 ft-lbs | 420 ft-lbs | 315 ft-lbs |
| 7/8" | 14 (Fine) | 215 ft-lbs | 161 ft-lbs | 475 ft-lbs | 356 ft-lbs | 675 ft-lbs | 506 ft-lbs |
| 1" | 12 (Fine) | 325 ft-lbs | 244 ft-lbs | 715 ft-lbs | 536 ft-lbs | 1020 ft-lbs | 765 ft-lbs |
Torque values for Metric bolts. Class indicated by numbers on bolt head (8.8, 10.9, 12.9). Higher numbers indicate greater strength. Metric property classes and their strength requirements are defined by the ISO 898-1 standard. Not sure of a bolt's thread pitch? Confirm it with the thread pitch chart before choosing coarse or fine values.
| Bolt Size | Pitch | Class 8.8 | Class 10.9 | Class 12.9 | |||
|---|---|---|---|---|---|---|---|
| Dry | Lub | Dry | Lub | Dry | Lub | ||
| M6 | 1.0mm (Coarse) | 9.9 Nm | 7.4 Nm | 14 Nm | 10.5 Nm | 16.5 Nm | 12.4 Nm |
| M8 | 1.25mm (Coarse) | 24 Nm | 18 Nm | 34 Nm | 25.5 Nm | 40 Nm | 30 Nm |
| M10 | 1.5mm (Coarse) | 48 Nm | 36 Nm | 68 Nm | 51 Nm | 80 Nm | 60 Nm |
| M12 | 1.75mm (Coarse) | 84 Nm | 63 Nm | 120 Nm | 90 Nm | 140 Nm | 105 Nm |
| M14 | 2.0mm (Coarse) | 135 Nm | 101 Nm | 190 Nm | 142 Nm | 225 Nm | 169 Nm |
| M16 | 2.0mm (Coarse) | 210 Nm | 157 Nm | 295 Nm | 221 Nm | 350 Nm | 262 Nm |
| M18 | 2.5mm (Coarse) | 290 Nm | 217 Nm | 410 Nm | 307 Nm | 485 Nm | 364 Nm |
| M20 | 2.5mm (Coarse) | 410 Nm | 307 Nm | 580 Nm | 435 Nm | 680 Nm | 510 Nm |
| M22 | 2.5mm (Coarse) | 550 Nm | 412 Nm | 780 Nm | 585 Nm | 920 Nm | 690 Nm |
| M24 | 3.0mm (Coarse) | 710 Nm | 532 Nm | 1000 Nm | 750 Nm | 1180 Nm | 885 Nm |
| M6 | 0.75mm (Fine) | 10.5 Nm | 7.9 Nm | 15 Nm | 11.2 Nm | 17.5 Nm | 13.1 Nm |
| M8 | 1.0mm (Fine) | 26 Nm | 19.5 Nm | 37 Nm | 27.7 Nm | 43 Nm | 32.2 Nm |
| M10 | 1.25mm (Fine) | 52 Nm | 39 Nm | 73 Nm | 54.7 Nm | 86 Nm | 64.5 Nm |
| M12 | 1.5mm (Fine) | 90 Nm | 67.5 Nm | 127 Nm | 95.2 Nm | 150 Nm | 112.5 Nm |
| M14 | 1.5mm (Fine) | 145 Nm | 109 Nm | 205 Nm | 154 Nm | 240 Nm | 180 Nm |
| M16 | 1.5mm (Fine) | 225 Nm | 169 Nm | 320 Nm | 240 Nm | 375 Nm | 281 Nm |
| M18 | 2.0mm (Fine) | 310 Nm | 232 Nm | 440 Nm | 330 Nm | 520 Nm | 390 Nm |
| M20 | 2.0mm (Fine) | 440 Nm | 330 Nm | 620 Nm | 465 Nm | 730 Nm | 547 Nm |
| M22 | 2.0mm (Fine) | 590 Nm | 442 Nm | 835 Nm | 626 Nm | 980 Nm | 735 Nm |
| M24 | 2.0mm (Fine) | 760 Nm | 570 Nm | 1075 Nm | 806 Nm | 1260 Nm | 945 Nm |
Never use dry torque specifications on lubricated fasteners. Over-tightening can cause bolt stretching, thread stripping, or catastrophic failure.
Quality torque wrenches for accurate bolt tightening. All recommendations based on accuracy, durability, and value.
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Dry torque values are for clean, unlubricated fasteners where friction between threads is at its normal level. Lubricated torque values (typically 20-30% lower) account for the reduced friction when threads have oil, grease, or anti-seize compound applied. Using dry torque specifications on lubricated bolts can cause over-tightening, which may stretch or break the bolt, strip threads, or cause joint failure.
SAE bolt grades indicate the tensile strength and hardness of the fastener. Grade 2 bolts (no head markings) are standard low-carbon steel suitable for general hardware. Grade 5 bolts (marked with 3 radial lines) are medium-carbon steel, commonly used in automotive and machinery applications. Grade 8 bolts (marked with 6 radial lines) are high-strength alloy steel for critical applications requiring maximum clamping force. Higher grades can withstand greater torque values.
To convert foot-pounds (ft-lbs) to Newton-meters (Nm), multiply by 1.3558. For example, 100 ft-lbs x 1.3558 = 135.58 Nm. To convert Newton-meters to foot-pounds, divide by 1.3558 or multiply by 0.7376. For quick mental math: ft-lbs x 1.36 is close enough for most applications, or Nm x 0.74 to go the other way. Use our converter tool above for precise calculations.
Coarse thread (UNC for SAE, standard pitch for metric) bolts have fewer threads per inch or a larger pitch. They are more resistant to stripping and cross-threading, easier to assemble, and better for softer materials. Fine thread (UNF for SAE, fine pitch for metric) bolts have more threads per inch, providing higher tensile strength, better vibration resistance, and more precise adjustment capability. Fine threads require slightly higher torque values and are more prone to galling in certain materials.
For general automotive and workshop use, start with a 1/2-inch drive click-type torque wrench covering 25-250 ft-lbs - this handles most common applications like lug nuts and engine work. Add a 3/8-inch drive wrench (10-80 ft-lbs) for smaller fasteners. For precision work or frequent use, consider a digital torque wrench with +/-2% accuracy. Quality brands include Tekton (best value), GearWrench (best digital), and CDI (professional grade). Always store click-type wrenches at their lowest setting to preserve calibration.
Standard bolt torque depends on diameter, thread pitch, and strength grade. Common dry values for SAE coarse-thread bolts: 1/4-20 takes 4 ft-lbs (Grade 2), 8 ft-lbs (Grade 5), or 12 ft-lbs (Grade 8); 3/8-16 takes 15, 31, or 44 ft-lbs; 1/2-13 takes 37, 75, or 105 ft-lbs. For metric coarse bolts: M8 takes 24 Nm (Class 8.8), 34 Nm (10.9), or 40 Nm (12.9); M10 takes 48, 68, or 80 Nm; M12 takes 84, 120, or 140 Nm. Grades are defined by SAE J429 and metric classes by ISO 898-1. Reduce values 20-30% for lubricated threads.
First identify three things about your bolt: its diameter and thread (such as 3/8-16 or M10 x 1.5), its strength grade from the head markings (SAE Grade 5 has 3 radial lines, Grade 8 has 6; metric bolts have 8.8, 10.9, or 12.9 stamped on the head), and whether the threads are dry or lubricated. Then find the row for your size, the column for your grade, and use the dry or lubricated value to match your thread condition. If the equipment manufacturer publishes a torque spec, it overrides any generic chart.