8.8 Bolt Torque Chart

Tightening torque and clamp force for Class 8.8 bolts from M1.6 to M64. For example, an M8 8.8 bolt needs about 26.6 N·m (19.6 ft·lb) with dry threads.

Quenched and tempered medium-carbon steel. The most common high-strength class for machinery, automotive and structural bolts.

Standard
Metric (ISO 898-1)
Yield strength used
640 MPa (93 ksi)
Tensile strength
800 MPa (116 ksi)
Sizes covered
M1.6 – M64
Class 8.8 — Coarse thread, tightening torque at 70% of yield
Size Threadpitch Clamp forcepreload Dryμ 0.15 Oiledμ 0.11 PTFE / moly pasteμ 0.06
M1.6 M1.6×0.350.35 mm 0.57 kN128 lbf 0.20 N·m0.15 ft·lb 0.15 N·m0.11 ft·lb 0.11 N·m0.08 ft·lb
M2 M2×0.40.4 mm 0.93 kN209 lbf 0.42 N·m0.31 ft·lb 0.31 N·m0.23 ft·lb 0.21 N·m0.16 ft·lb
M2.5 M2.5×0.450.45 mm 1.52 kN342 lbf 0.84 N·m0.62 ft·lb 0.63 N·m0.46 ft·lb 0.42 N·m0.31 ft·lb
M3 M3×0.50.5 mm 2.25 kN507 lbf 1.43 N·m1.05 ft·lb 1.08 N·m0.79 ft·lb 0.72 N·m0.53 ft·lb
M3.5 M3.5×0.60.6 mm 3.04 kN682 lbf 2.20 N·m1.62 ft·lb 1.66 N·m1.22 ft·lb 1.11 N·m0.82 ft·lb
M4 M4×0.70.7 mm 3.93 kN884 lbf 3.29 N·m2.43 ft·lb 2.48 N·m1.83 ft·lb 1.67 N·m1.23 ft·lb
M5 M5×0.80.8 mm 6.35 kN1428 lbf 6.39 N·m4.71 ft·lb 4.80 N·m3.54 ft·lb 3.22 N·m2.38 ft·lb
M6 M6×11 mm 9.02 kN2027 lbf 11.0 N·m8.15 ft·lb 8.32 N·m6.13 ft·lb 5.59 N·m4.12 ft·lb
M7 M7×11 mm 12.9 kN2907 lbf 17.9 N·m13.2 ft·lb 13.4 N·m9.88 ft·lb 8.90 N·m6.57 ft·lb
M8 M8×1.251.25 mm 16.4 kN3687 lbf 26.6 N·m19.6 ft·lb 20.0 N·m14.7 ft·lb 13.3 N·m9.84 ft·lb
M10 M10×1.51.5 mm 26.0 kN5840 lbf 52.0 N·m38.3 ft·lb 39.0 N·m28.7 ft·lb 26.0 N·m19.2 ft·lb
M12 M12×1.751.75 mm 37.8 kN8487 lbf 89.2 N·m65.8 ft·lb 66.8 N·m49.3 ft·lb 44.5 N·m32.8 ft·lb
M14 M14×22 mm 51.7 kN11626 lbf 141.8 N·m104.6 ft·lb 106.2 N·m78.3 ft·lb 70.6 N·m52.1 ft·lb
M16 M16×22 mm 70.2 kN15779 lbf 217.3 N·m160.3 ft·lb 161.9 N·m119.4 ft·lb 106.6 N·m78.6 ft·lb
M18 M18×2.52.5 mm 86.2 kN19385 lbf 303.5 N·m223.9 ft·lb 227.1 N·m167.5 ft·lb 150.7 N·m111.1 ft·lb
M20 M20×2.52.5 mm 109.7 kN24654 lbf 424.9 N·m313.4 ft·lb 316.6 N·m233.5 ft·lb 208.4 N·m153.7 ft·lb
M22 M22×2.52.5 mm 135.9 kN30557 lbf 579.7 N·m427.6 ft·lb 430.5 N·m317.5 ft·lb 281.2 N·m207.4 ft·lb
M24 M24×33 mm 157.9 kN35502 lbf 731.9 N·m539.8 ft·lb 545.5 N·m402.3 ft·lb 359.1 N·m264.9 ft·lb
M27 M27×33 mm 205.8 kN46269 lbf 1074.4 N·m792.4 ft·lb 797.2 N·m588.0 ft·lb 520.1 N·m383.6 ft·lb
M30 M30×3.53.5 mm 251.1 kN56459 lbf 1462.1 N·m1078.4 ft·lb 1086.7 N·m801.5 ft·lb 711.3 N·m524.6 ft·lb
M33 M33×3.53.5 mm 310.7 kN69851 lbf 1968.2 N·m1451.6 ft·lb 1458.5 N·m1075.7 ft·lb 948.8 N·m699.8 ft·lb
M36 M36×44 mm 365.9 kN82256 lbf 2537.8 N·m1871.8 ft·lb 1883.4 N·m1389.1 ft·lb 1228.9 N·m906.4 ft·lb
M39 M39×44 mm 437.1 kN98272 lbf 3272.1 N·m2413.3 ft·lb 2422.0 N·m1786.4 ft·lb 1571.9 N·m1159.4 ft·lb
M42 M42×4.54.5 mm 502.2 kN112892 lbf 4060.9 N·m2995.2 ft·lb 3010.0 N·m2220.0 ft·lb 1959.0 N·m1444.9 ft·lb
M45 M45×4.54.5 mm 585.1 kN131533 lbf 5052.8 N·m3726.8 ft·lb 3737.0 N·m2756.3 ft·lb 2421.3 N·m1785.8 ft·lb
M48 M48×55 mm 660.0 kN148367 lbf 6120.7 N·m4514.4 ft·lb 4531.9 N·m3342.5 ft·lb 2943.0 N·m2170.7 ft·lb
M52 M52×55 mm 787.5 kN177039 lbf 7832.1 N·m5776.6 ft·lb 5786.0 N·m4267.6 ft·lb 3740.0 N·m2758.5 ft·lb
M56 M56×5.55.5 mm 909.4 kN204452 lbf 9769.5 N·m7205.6 ft·lb 7221.4 N·m5326.3 ft·lb 4673.4 N·m3446.9 ft·lb
M60 M60×5.55.5 mm 1058.2 kN237889 lbf 12077.4 N·m8907.8 ft·lb 8910.9 N·m6572.3 ft·lb 5744.3 N·m4236.8 ft·lb
M64 M64×66 mm 1198.8 kN269509 lbf 14550.0 N·m10731.5 ft·lb 10743.4 N·m7924.0 ft·lb 6936.9 N·m5116.4 ft·lb
Class 8.8 — Fine thread, tightening torque at 70% of yield
Size Threadpitch Clamp forcepreload Dryμ 0.15 Oiledμ 0.11 PTFE / moly pasteμ 0.06
M1.6 M1.6×0.20.2 mm 0.70 kN158 lbf 0.24 N·m0.18 ft·lb 0.18 N·m0.13 ft·lb 0.12 N·m0.09 ft·lb
M2 M2×0.250.25 mm 1.10 kN247 lbf 0.47 N·m0.35 ft·lb 0.35 N·m0.26 ft·lb 0.23 N·m0.17 ft·lb
M2.5 M2.5×0.350.35 mm 1.66 kN373 lbf 0.90 N·m0.66 ft·lb 0.67 N·m0.49 ft·lb 0.44 N·m0.32 ft·lb
M3 M3×0.350.35 mm 2.51 kN565 lbf 1.55 N·m1.15 ft·lb 1.15 N·m0.85 ft·lb 0.75 N·m0.55 ft·lb
M3.5 M3.5×0.350.35 mm 3.54 kN796 lbf 2.47 N·m1.82 ft·lb 1.83 N·m1.35 ft·lb 1.18 N·m0.87 ft·lb
M4 M4×0.50.5 mm 4.39 kN986 lbf 3.58 N·m2.64 ft·lb 2.66 N·m1.96 ft·lb 1.74 N·m1.29 ft·lb
M5 M5×0.50.5 mm 7.22 kN1624 lbf 7.03 N·m5.19 ft·lb 5.20 N·m3.84 ft·lb 3.37 N·m2.48 ft·lb
M6 M6×0.750.75 mm 9.87 kN2219 lbf 11.8 N·m8.73 ft·lb 8.81 N·m6.50 ft·lb 5.78 N·m4.27 ft·lb
M7 M7×0.750.75 mm 13.9 kN3136 lbf 18.9 N·m14.0 ft·lb 14.0 N·m10.4 ft·lb 9.13 N·m6.73 ft·lb
M8 M8×11 mm 17.5 kN3945 lbf 28.0 N·m20.6 ft·lb 20.8 N·m15.4 ft·lb 13.7 N·m10.1 ft·lb
M10 M10×1.251.25 mm 27.4 kN6164 lbf 54.1 N·m39.9 ft·lb 40.3 N·m29.7 ft·lb 26.5 N·m19.5 ft·lb
M12 M12×1.51.5 mm 39.5 kN8876 lbf 92.2 N·m68.0 ft·lb 68.7 N·m50.7 ft·lb 45.2 N·m33.3 ft·lb
M14 M14×1.51.5 mm 55.8 kN12544 lbf 150.1 N·m110.7 ft·lb 111.2 N·m82.0 ft·lb 72.4 N·m53.4 ft·lb
M16 M16×1.51.5 mm 74.9 kN16844 lbf 228.0 N·m168.2 ft·lb 168.4 N·m124.2 ft·lb 108.7 N·m80.2 ft·lb
M18 M18×1.51.5 mm 96.9 kN21778 lbf 330.9 N·m244.0 ft·lb 243.5 N·m179.6 ft·lb 156.1 N·m115.1 ft·lb
M20 M20×1.51.5 mm 121.6 kN27344 lbf 458.5 N·m338.2 ft·lb 336.5 N·m248.2 ft·lb 214.6 N·m158.3 ft·lb
M22 M22×1.51.5 mm 149.2 kN33543 lbf 620.7 N·m457.8 ft·lb 454.6 N·m335.3 ft·lb 288.4 N·m212.7 ft·lb
M24 M24×22 mm 172.2 kN38716 lbf 780.1 N·m575.4 ft·lb 574.1 N·m423.5 ft·lb 368.2 N·m271.6 ft·lb
M27 M27×22 mm 222.1 kN49928 lbf 1136.1 N·m838.0 ft·lb 833.6 N·m614.8 ft·lb 531.0 N·m391.6 ft·lb
M30 M30×22 mm 278.3 kN62564 lbf 1576.5 N·m1162.8 ft·lb 1153.9 N·m851.1 ft·lb 731.4 N·m539.4 ft·lb
M33 M33×22 mm 340.8 kN76623 lbf 2105.5 N·m1552.9 ft·lb 1538.3 N·m1134.6 ft·lb 971.2 N·m716.3 ft·lb
M36 M36×33 mm 387.5 kN87112 lbf 2647.1 N·m1952.4 ft·lb 1947.9 N·m1436.7 ft·lb 1248.7 N·m921.0 ft·lb
M39 M39×33 mm 460.7 kN103573 lbf 3400.3 N·m2508.0 ft·lb 2497.2 N·m1841.8 ft·lb 1594.0 N·m1175.7 ft·lb
M42 M42×33 mm 540.3 kN121459 lbf 4284.3 N·m3159.9 ft·lb 3140.8 N·m2316.5 ft·lb 1997.4 N·m1473.2 ft·lb
M45 M45×33 mm 626.2 kN140769 lbf 5309.3 N·m3915.9 ft·lb 3886.3 N·m2866.4 ft·lb 2463.4 N·m1816.9 ft·lb
M48 M48×33 mm 718.4 kN161502 lbf 6512.2 N·m4803.1 ft·lb 4760.1 N·m3510.9 ft·lb 3008.0 N·m2218.6 ft·lb
M52 M52×44 mm 819.1 kN184130 lbf 8060.0 N·m5944.8 ft·lb 5919.2 N·m4365.8 ft·lb 3778.3 N·m2786.7 ft·lb
M56 M56×44 mm 960.5 kN215927 lbf 10167.0 N·m7498.8 ft·lb 7453.3 N·m5497.3 ft·lb 4739.6 N·m3495.7 ft·lb
M60 M60×44 mm 1113.2 kN250255 lbf 12530.4 N·m9242.0 ft·lb 9173.1 N·m6765.7 ft·lb 5815.7 N·m4289.4 ft·lb
M64 M64×44 mm 1277.1 kN287115 lbf 15233.1 N·m11235.4 ft·lb 11137.7 N·m8214.8 ft·lb 7042.4 N·m5194.2 ft·lb

Preload is 70% of yield. Torque per ISO 16047 / VDI 2230 for standard hex heads, with the same friction μ in the threads and under the head. Click a size for wrench size, tap drill and a worked example. Always follow the manufacturer's value where one exists.

Frequently asked questions

What is the torque for an M8 8.8 bolt?

About 26.6 N·m (19.6 ft·lb) with dry threads and 20.0 N·m (14.7 ft·lb) with oiled threads (M8×1.25, 70% of yield, clamp force 16.4 kN).

What is the torque for an M10 8.8 bolt?

About 52.0 N·m (38.3 ft·lb) with dry threads and 39.0 N·m (28.7 ft·lb) with oiled threads (M10×1.5, 70% of yield, clamp force 26.0 kN).

What is the torque for an M12 8.8 bolt?

About 89.2 N·m (65.8 ft·lb) with dry threads and 66.8 N·m (49.3 ft·lb) with oiled threads (M12×1.75, 70% of yield, clamp force 37.8 kN).

Other grades

4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9 Grade 2 Grade 5 Grade 8 A307 A325 A490 A574 A2-70 A4-70 A4-80
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