Portland Bolt Logo Part
Home > Technical Information > Bolt Torque Chart

Bolt Torque Chart

Suggested Starting Values

The below estimated torque calculations are only offered as a guide. Use of its content by anyone is the sole responsibility of that person and they assume all risk. Due to many variables that affect the torque-tension relationship like human error, surface texture, and lubrication the only way to determine the correct torque is through experimentation under actual joint and assembly conditions.

ASTM A307

Bolt Size TPI Proof
Load (lbs)1
Clamp
Load (lbs)2
Tightening Torque (ft lbs)
Galv+Waxed Galv Plain
14 20 1145 859 2 4 4
516 18 1886 1415 4 9 7
38 16 2790 2093 7 16 13
716 14 3827 2870 10 26 21
12 13 5108 3831 16 40 32
916 12 6552 4914 23 58 46
58 11 8136 6102 32 79 64
34 10 12024 9018 56 141 113
78 9 15200 11400 83 208 166
1 8 20000 15000 125 313 250
118 7 25200 18900 177 443 354
114 7 32000 24000 250 625 500
138 6 38100 28575 327 819 655
112 6 46400 34800 435 1088 870
134 5 68400 51300 748 1870 1496
2 412 90000 67500 1125 2813 2250
214 412 117000 87750 1645 4113 3291
212 4 144000 108000 2250 5625 4500
234 4 177480 133110 3050 7626 6101
3 4 214920 161190 4030 10074 8060
314 4 255600 191700 5192 12980 10384
312 4 299880 224910 6560 16400 13120
334 4 347760 260820 8151 20377 16301
4 4 398880 299160 9972 24930 19944

SAE GRADE 2

Bolt Size TPI Proof
Load (lbs) 1
Clamp
Load (lbs) 2
Tightening Torque (ft lbs)
Galv+Waxed Galv Plain
14 20 1750 1313 3 7 5
516 18 2900 2175 6 14 11
38 16 4250 3188 10 25 20
716 14 5850 4388 16 40 32
12 13 7800 5850 24 61 49
916 12 10000 7500 35 88 70
58 11 12400 9300 48 121 97
34 10 18400 13800 86 216 173
78 9 15200 11400 83 208 166
1 8 20000 15000 125 313 250
118 7 25200 18900 177 443 354
114 7 32000 24000 250 625 500
138 6 38100 28575 327 819 655
112 6 46400 34800 435 1088 870

ASTM A325

Bolt Size TPI Tension Tightening Torque Range (ft lbs) (Min - Max)
Min Max Galv+Waxed Plain
12 13 12000 14000 50 - 58 100 - 117
58 11 19000 23000 99 - 120 198 - 240
34 10 28000 34000 175 - 213 350 - 425
78 9 39000 47000 284 - 343 569 - 685
1 8 51000 61000 425 - 508 850 - 1017
118 7 56000 67000 525 - 625 1050 - 1256
114 7 71000 85000 740 - 885 1479 - 1771
138 6 85000 102000 974 - 1169 1948 - 2338
112 6 103000 124000 1288 - 1550 2575 - 3100

ASTM A449 / SAE GRADE 5

Bolt Size TPI Proof
Load (lbs) 1
Clamp
Load (lbs) 2
Tightening Torque (ft lbs)
Galv+Waxed Galv Plain
14 20 2700 2025 4 11 8
516 18 4450 3338 9 22 17
38 16 6600 4950 15 39 31
716 14 9050 6788 25 62 49
12 13 12050 9038 38 94 75
916 12 15450 11588 54 136 109
58 11 19200 14400 75 188 150
34 10 28400 21300 133 333 266
78 9 39250 29438 215 537 429
1 8 51500 38625 322 805 644
118 7 56450 42338 397 992 794
114 7 71700 53775 560 1400 1120
138 6 85450 64088 734 1836 1469
112 6 104000 78000 975 2438 1950
134 5 104500 78375 1143 2857 2286
2 412 137500 103125 1719 4297 3438
214 412 178750 134063 2514 6284 5027
212 4 220000 165000 3438 8594 6875
234 4 271150 203363 4660 11651 9321
3 4 328350 246263 6157 15391 12313

SAE J429 grade 5 bolts do not exceed 1-1/2" diameter.

ASTM A193 B7

Bolt Size TPI Proof
Load (lbs) 1
Clamp
Load (lbs) 2
Tightening Torque (ft lbs)
Galv+Waxed Galv Plain
14 20 3,350 2,513 5 13 10
516 18 5,500 4,125 11 27 21
38 16 8,150 6,113 19 48 38
716 14 11,150 8,363 30 76 61
12 13 14,900 11,175 47 116 93
916 12 19,100 14,325 67 168 134
58 11 23,750 17,813 93 232 186
34 10 35,050 26,288 164 411 329
78 9 48,500 36,375 265 663 530
1 8 63,650 47,738 398 995 796
118 7 80,100 60,075 563 1,408 1,126
8 82,934 62,201 583 1,458 1,166
114 7 101,750 76,313 795 1,987 1,590
8 105,006 78,754 820 2,051 1,641
138 6 121,300 90,975 1,042 2,606 2,085
8 129,492 97,119 1,113 2,782 2,226
112 6 147,550 110,663 1,383 3,458 2,767
8 156,687 117,515 1,469 3,672 2,938
134 5 199,500 149,625 - - 4,364
8 218,400 163,800 - - 4,778
2 412 262,500 196,875 - - 6,563
8 290,850 218,138 - - 7,271
214 412 341,250 255,938 - - 9,598
8 373,801 280,351 - - 10,513
212 4 420,000 315,000 - - 13,125
8 466,200 349,650 - - 14,569
234 4 468,500 351,263 - - 16,100
8 515,851 386,888 - - 17,732
3 4 567,150 425,363 - - 21,268
8 618,451 463,838 - - 23,192
314 4 674,500 505,875 - - 27,402
8 730,550 547,913 - - 29,679
312 4 791,350 593,513 - - 34,622
8 851,201 638,401 - - 37,240
334 4 917700 688275 - - 43017
8 982,300 736,725 - - 46,045
4 4 1052600 789450 - - 52630
8 1,121,950 841,463 - - 56,098

ASTM A490

Bolt Size TPI Tension (lbs) Tightening Torque Range (ft lbs) (Min - Max)
Min Max Lubricated Plain
12 13 15000 18000 63 - 75 125 - 150
58 11 24000 29000 125 - 151 250 - 302
34 10 35000 42000 219 - 263 438 - 525
78 9 49000 59000 357 - 430 715 - 860
1 8 64000 77000 533 - 642 1067 - 1283
118 7 80000 96000 750 - 900 1500 - 1800
114 7 102000 122000 1063 - 1271 2125 - 2542
138 6 121000 145000 1386 - 1661 2773 - 3323
112 6 148000 178000 1850 - 2225 3700 - 4450

ASTM A354-BD / SAE GRADE 8

Bolt Size TPI Proof
Load (lbs) 1
Clamp
Load (lbs) 2
Tightening Torque (ft lbs)
Lubricated Plain
14 20 3800 2850 6 12
516 18 6300 4725 12 25
38 16 9300 6975 22 44
716 14 12750 9563 35 70
12 13 17050 12788 53 107
916 12 21850 16388 77 154
58 11 27100 20325 106 212
34 10 40100 30075 188 376
78 9 55450 41588 303 606
1 8 72700 54525 454 909
118 7 91550 68663 644 1287
114 7 120000 90000 938 1875
138 6 138600 103950 1191 2382
112 6 168600 126450 1581 3161
134 5 228000 171000 2494 4988
2 412 300000 225000 3750 7500
214 412 390000 292500 5484 10969
212 4 480000 360000 7500 15000
234 4 517650 388238 8897 17794
3 4 626850 470138 11753 23507
314 4 745500 559125 15143 30286
312 4 874650 655988 19133 38266
334 4 1014300 760725 23773 47545
4 4 1163400 872550 29085 58100

SAE J429 grade 8 bolts do not exceed 1-1/2" diameter.

1 - Proofload is the published number that full size headed bolts are tested to. The bolt is stressed up to the proofload value, and if there is no deformation, elongation, or fracture, then the bolt is deemed to have passed. For bolting specifications that do not have a published proofload, it is usually calculated at 92% of ultimate yield strength.
2 - Clampload is calculated at 75% of proofload. This is done to allow a safety buffer so that the bolt does not get too close to the proofload value. If you exceed the proofload value when tensioning the bolt, you run the risk of bolt failure. Clampload is only a estimated number, there maybe situations where the engineer calls for the bolts to be tensioned to a different value.
    Notes:

  1. Values calculated using industry accepted formula T = KDP where T = Torque, K = torque coefficient (dimensionless), D = nominal diameter (inches), P = bolt clamp load, lb.
  2. K values: waxed (e.g. pressure wax as supplied on high strength nuts) = .10, hot dip galvanized = .25, and plain non-plated bolts (as received) = .20.
  3. Torque has been converted into ft/lbs by dividing the result of the formula by 12
  4. All calculations are for Coarse Thread Series (UNC).
  5. Grade 2 calculations only cover fasteners 14"-34" in diameter up to 6" long; for longer fasteners the torque is reduced significantly.
  6. Clamp loads are based on 75% of the minimum proof loads for each grade and size.
  7. Proof load, stress area, yield strength, and other data is based on IFI 7th Edition (2003) Technical Data N-68, SAE J429, ASTM A307, A325, A354, A449, and A490.