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Bolt torque chart

Suggested starting torque values for common ASTM and SAE bolt grades. Torque is a convenient shop estimate — it is not a substitute for the clamp load your engineer specified. Use these tables to brief a take-off or compare finishes; verify final torque under your actual joint conditions.

ASTM A307SAE Grade 2ASTM A325ASTM A449ASTM A193 B7ASTM A490ASTM A354 BD Specifications Isolation kits Request a quote

Important — read before using these numbers

The values below are starting guides only. Anyone who uses them assumes responsibility for verifying the correct torque for their joint. Lubrication, plating, thread condition, washer hardness, human error, and surface texture all change the torque–tension relationship.

The only reliable way to confirm correct tension is testing under actual assembly conditions, or using a tension-indicating method named in the project specification. When in doubt, follow the engineer of record — or ask us to help source the fasteners and related documentation.

A307 Grade 2 A325 A449 / Grade 5 B7 / L7 / A354 BC A490 A354 BD / Grade 8

ASTM A307

Carbon steel bolts and studs for general-purpose fastening.

Bolt sizeTPIProof load (lbs)Clamp load (lbs) Tightening torque (ft·lbs)
Galv + waxedGalvanizedPlain
1/420 1,053790 243
5/1618 1,7351,302 387
3/816 2,5671,925 61512
7/1614 3,5212,640 102419
1/213 4,7003,525 153729
9/1612 6,0284,521 215342
5/811 7,4855,614 297358
3/410 11,0628,297 52130104
7/89 15,30111,476 84209167
18 20,07115,053 125314251
1-1/87 25,27118,953 178444355
1-1/47 32,09324,070 251627501
1-3/86 38,25428,690 329822657
1-1/26 46,53434,900 4361,091873
1-3/45 62,92847,196 6881,7211,377
24-1/2 82,80062,100 1,0352,5882,070
2-1/44-1/2 107,64080,730 1,5143,7843,027
2-1/24 132,48099,360 2,0705,1254,140
2-3/44 163,282122,461 2,8067,0165,613
34 197,726148,295 3,7079,2687,415
3-1/44 235,152176,364 4,77711,9419,553
3-1/24 275,890206,917 6,03515,08812,070
3-3/44 319,939239,954 7,49918,74614,997
44 366,970275,227 9,17422,93618,348

SAE Grade 2

Low-carbon commercial fasteners (SAE J429 Grade 2).

Grade 2 guidance is typically limited for smaller diameters and shorter lengths; longer fasteners often need reduced torque.

Bolt sizeTPIProof load (lbs)Clamp load (lbs) Tightening torque (ft·lbs)
Galv + waxedGalvanizedPlain
1/420 1,7501,313 375
5/1618 2,9002,175 61411
3/816 4,2503,188 102520
7/1614 5,8504,388 164032
1/213 7,8005,850 246149
9/1612 10,0007,500 358870
5/811 12,4009,300 4812197
3/410 18,40013,800 86216173
7/89 15,20011,400 83208166
18 20,00015,000 125313250
1-1/87 25,20018,900 177443354
1-1/47 32,00024,000 250625500
1-3/86 38,10028,575 327819655
1-1/26 46,40034,800 4351,088870

ASTM A325 / F3125 Grade A325

Structural bolts shown as tension windows with torque ranges.

A325 is a legacy designation; new work usually references ASTM F3125 Grade A325.

Bolt sizeTPITension min (lbs)Tension max (lbs) Torque range (ft·lbs)
Galv + waxedPlain
1/213 12,00014,000 50 – 58100 – 117
5/811 19,00023,000 99 – 120198 – 240
3/410 28,00034,000 175 – 213350 – 425
7/89 39,00047,000 284 – 343569 – 685
18 51,00061,000 425 – 508850 – 1,017
1-1/87 64,00077,000 600 – 7221,200 – 1,444
1-1/47 81,00098,000 844 – 1,0211,687 – 2,042
1-3/86 97,000117,000 1,111 – 1,3412,223 – 2,681
1-1/26 118,000143,000 1,475 – 1,7882,950 – 3,575

ASTM A449 / SAE Grade 5

Quenched and tempered bolts for general engineering.

SAE J429 Grade 5 bolts typically do not exceed 1-1/2″ diameter.

Bolt sizeTPIProof load (lbs)Clamp load (lbs) Tightening torque (ft·lbs)
Galv + waxedGalvanizedPlain
1/420 2,7002,025 4118
5/1618 4,4503,338 92217
3/816 6,6004,950 153931
7/1614 9,0506,788 256249
1/213 12,0509,038 389475
9/1612 15,45011,588 54136109
5/811 19,20014,400 75188150
3/410 28,40021,300 133333266
7/89 39,25029,438 215537429
18 51,50038,625 322805644
1-1/87 56,45042,338 397992794
1-1/47 71,70053,775 5601,4001,120
1-3/86 85,45064,088 7341,8361,469
1-1/26 104,00078,000 9752,4381,950
1-3/45 104,50078,375 1,1432,8572,286
24-1/2 137,500103,125 1,7194,2973,438
2-1/44-1/2 178,750134,063 2,5146,2845,027
2-1/24 220,000165,000 3,4388,5946,875
2-3/44 271,150203,363 4,66011,6519,321
34 328,350246,263 6,15715,39112,313

ASTM A193 B7 / A320 L7 / A354 BC

High-strength alloy studs and bolts common in industrial and low-temperature service.

Where a second TPI is shown (for example 8), it is a fine-thread / 8UN series row. A dash means that finish was not published for that row.

Bolt sizeTPIProof load (lbs)Clamp load (lbs) Tightening torque (ft·lbs)
Galv + waxedGalvanizedPlain
1/420 3,3502,513 51310
5/1618 5,5004,125 112721
3/816 8,1506,113 194838
7/1614 11,1508,363 307661
1/213 14,90011,175 4711693
9/1612 19,10014,325 67168134
5/811 23,75017,813 93232186
3/410 35,05026,288 164411329
7/89 48,50036,375 265663530
18 63,65047,738 398995796
1-1/87 80,10060,075 5631,4081,126
1-1/88 82,93462,201 5831,4581,166
1-1/47 101,75076,313 7951,9871,590
1-1/48 105,00678,754 8202,0511,641
1-3/86 121,30090,975 1,0422,6062,085
1-3/88 129,49297,119 1,1132,7822,226
1-1/26 147,550110,663 1,3833,4582,767
1-1/28 156,687117,515 1,4693,6722,938
1-3/45 199,500149,625 2,1825,4554,364
1-3/48 218,400163,800 ——4,778
24-1/2 262,500196,875 3,2818,2036,563
28 290,850218,138 ——7,271
2-1/44-1/2 341,250255,938 4,79911,9979,598
2-1/48 373,801280,351 ——10,513
2-1/24 420,000315,000 6,56316,40613,125
2-1/28 466,200349,650 ——14,569
2-3/44 468,500351,263 8,05020,12416,100
2-3/48 515,851386,888 ——17,732
34 567,150425,363 10,63426,58521,268
38 618,451463,838 ——23,192
3-1/44 674,500505,875 13,70134,25227,402
3-1/48 730,550547,913 ——29,679
3-1/24 791,350593,513 17,31143,27734,622
3-1/28 851,201638,401 ——37,240
3-3/44 917,700688,275 21,50953,77143,017
3-3/48 982,300736,725 ——46,045
44 1,052,600789,450 26,31565,78852,630
48 1,121,950841,463 ——56,098

ASTM A490 / F3125 Grade A490

Higher-strength structural bolts — tension windows with plain vs lubricated torque ranges.

A490 is a legacy designation; new work usually references ASTM F3125 Grade A490. Do not hot-dip galvanize A490 / Grade A490 without an approved coating system.

Bolt sizeTPITension min (lbs)Tension max (lbs) Torque range (ft·lbs)
PlainLubricated
1/213 15,00018,000 125 – 15063 – 75
5/811 24,00029,000 250 – 302125 – 151
3/410 35,00042,000 438 – 525219 – 263
7/89 49,00059,000 715 – 860357 – 430
18 64,00077,000 1,067 – 1,283533 – 642
1-1/87 80,00096,000 1,500 – 1,800750 – 900
1-1/47 102,000122,000 2,125 – 2,5421,063 – 1,271
1-3/86 121,000145,000 2,773 – 3,3231,386 – 1,661
1-1/26 148,000178,000 3,700 – 4,4501,850 – 2,225

ASTM A354 BD / SAE Grade 8

Highest common quenched-and-tempered commercial grades.

SAE J429 Grade 8 bolts typically do not exceed 1-1/2″ diameter.

Bolt sizeTPIProof load (lbs)Clamp load (lbs) Tightening torque (ft·lbs)
PlainLubricated
1/420 3,8002,850 126
5/1618 6,3004,725 2512
3/816 9,3006,975 4422
7/1614 12,7509,563 7035
1/213 17,05012,788 10753
9/1612 21,85016,388 15477
5/811 27,10020,325 212106
3/410 40,10030,075 376188
7/89 55,45041,588 606303
18 72,70054,525 909454
1-1/87 91,55068,663 1,287644
1-1/47 120,00090,000 1,875938
1-3/86 138,600103,950 2,3821,191
1-1/26 168,600126,450 3,1611,581
1-3/45 228,000171,000 4,9882,494
24-1/2 300,000225,000 7,5003,750
2-1/44-1/2 390,000292,500 10,9695,484
2-1/24 480,000360,000 15,0007,500
2-3/44 517,650388,238 17,7948,897
34 626,850470,138 23,50711,753
3-1/44 745,500559,125 30,28615,143
3-1/24 874,650655,988 38,26619,133
3-3/44 1,014,300760,725 47,54523,773
44 1,163,400872,550 58,10029,085

How these starting values are typically calculated

Industry practice often uses T = K × D × P, then converts inch-pounds to foot-pounds by dividing by 12.

  • T = torque (in·lbs before conversion)
  • K = friction factor — common starting assumptions: waxed ≈ 0.10, plain “as received” ≈ 0.20, hot-dip galvanized ≈ 0.25
  • D = nominal bolt diameter (inches)
  • P = target clamp load (lbs)
  • Clamp load in these tables is generally taken as about 75% of proof load so you are not riding the proof-load edge.
  • Proof load is the published (or estimated) load used in proof testing of headed bolts; where a standard does not publish proof load, it is often estimated near 92% of minimum yield.
  • Tables assume coarse thread (UNC) unless a second TPI row is shown.
  • Reference data commonly cited in industry guides includes IFI technical data and the ASTM / SAE standards named on each section.
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