Metric bolt torque chart.

Guide torque values for metric coarse bolts, by size, property class and thread condition. An M12 class 8.8 bolt needs about 88 N·m dry (K = 0.20) and about 57 N·m lubricated (K = 0.13) for the same 36.7 kN preload. These are calculated guide values, not a joint design.

Reviewed 11 Nov 2026 · Based on ISO 898-1:2013 (proof stress, stress area); T = K · F · d with F = 75% of proof load; typical nut factors K · Report an error

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Questions on this?

How the values are calculated.

T = K × F × d. Preload F is 75% of the proof load: proof stress Sp from ISO 898-1 times the tensile stress area As. K is the nut factor, which depends on the finish and lubrication; the values below are typical, and real friction varies widely. For a calculated joint, use VDI 2230 or the fastener supplier's tested values; the value specified by the equipment maker or designer always governs.

Calculate other preloads or sizes with the torque calculator

Guide torque (N·m), Plain or black, dry; Zinc plated, dry, K = 0.2
Size	Class 8.8	Class 10.9	Class 12.9	Class 8.8 (ft·lbf)
M6	11	15	18	8
M8	25	36	43	19
M10	50	72	84	37
M12	88	126	147	65
M14	141	201	235	104
M16	218	312	365	161
M18	312	431	504	230
M20	441	610	712	325
M22	601	831	971	443
M24	761	1,053	1,231	562
M27	1,116	1,544	1,805	823
M30	1,514	2,094	2,447	1,116
M36	2,646	3,661	4,278	1,952

Source: Calculated: T = 0.2 × F × d, F = 0.75 × Sp × As (ISO 898-1). Guide values only.

Guide torque (N·m), Hot-dip galvanized, K = 0.25
Size	Class 8.8	Class 10.9	Class 12.9	Class 8.8 (ft·lbf)
M6	13	19	22	10
M8	32	46	53	23
M10	63	90	105	47
M12	110	157	184	81
M14	176	252	294	130
M16	273	390	456	201
M18	390	539	630	287
M20	551	762	890	406
M22	751	1,039	1,214	554
M24	952	1,317	1,539	702
M27	1,395	1,930	2,256	1,029
M30	1,892	2,617	3,059	1,396
M36	3,308	4,576	5,347	2,440

Source: Calculated: T = 0.25 × F × d, F = 0.75 × Sp × As (ISO 898-1). Guide values only.

Guide torque (N·m), Lightly oiled, K = 0.18
Size	Class 8.8	Class 10.9	Class 12.9	Class 8.8 (ft·lbf)
M6	9	14	16	7
M8	23	33	38	17
M10	45	65	76	33
M12	79	113	132	58
M14	127	181	212	93
M16	196	281	328	145
M18	281	388	454	207
M20	397	549	641	293
M22	541	748	874	399
M24	685	948	1,108	505
M27	1,005	1,390	1,624	741
M30	1,362	1,884	2,202	1,005
M36	2,382	3,294	3,850	1,757

Source: Calculated: T = 0.18 × F × d, F = 0.75 × Sp × As (ISO 898-1). Guide values only.

Guide torque (N·m), Lubricated (MoS₂ paste or wax), K = 0.13
Size	Class 8.8	Class 10.9	Class 12.9	Class 8.8 (ft·lbf)
M6	7	10	11	5
M8	17	24	28	12
M10	33	47	55	24
M12	57	82	96	42
M14	91	131	153	67
M16	142	203	237	105
M18	203	280	328	149
M20	286	396	463	211
M22	390	540	631	288
M24	495	685	800	365
M27	726	1,004	1,173	535
M30	984	1,361	1,591	726
M36	1,720	2,379	2,781	1,269

Source: Calculated: T = 0.13 × F × d, F = 0.75 × Sp × As (ISO 898-1). Guide values only.

Preload at 75% of proof load (kN), all finishes
Size	Stress area As (mm²)	Class 8.8	Class 10.9	Class 12.9
M6	20.1	8.8	12.5	14.6
M8	36.6	15.9	22.8	26.6
M10	58.0	25.2	36.1	42.2
M12	84.3	36.7	52.5	61.3
M14	115.4	50.2	71.9	84.0
M16	156.7	68.2	97.5	114.0
M18	192.5	86.6	119.8	140.0
M20	244.8	110.2	152.4	178.1
M22	303.4	136.5	188.9	220.7
M24	352.5	158.6	219.4	256.4
M27	459.4	206.7	286.0	334.2
M30	560.6	252.3	349.0	407.8
M36	816.7	367.5	508.4	594.2

Source: Calculated: F = 0.75 × Sp × As; Sp and the As formula from ISO 898-1:2013. Class 8.8 uses Sp 580 MPa up to M16 and 600 MPa above.

Reference values, not a design.

Values are the nominal figures of the cited standards, or calculated from them where marked. The governing standard and your drawing always take precedence.

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Questions buyers ask.

What is the torque for an M12 8.8 bolt?

About 88 N·m for a dry plain or zinc-plated thread (K = 0.20), giving about 36.7 kN preload at 75% of proof load. Lubricated with MoS₂ paste or wax (K = 0.13), about 57 N·m gives the same preload. Follow the value your designer or equipment maker specifies.

Why are there different torque values for the same bolt?

Most tightening torque is lost to friction under the head and in the thread. The nut factor K captures that friction, so a lubricated bolt reaches the same preload at a lower torque. Using a dry value on a lubricated bolt can overstretch or break it.

Do stainless A2 and A4 bolts use this chart?

No. This chart uses the proof stresses of ISO 898-1 for carbon and alloy steel classes 8.8, 10.9 and 12.9. Stainless bolts to ISO 3506-1 have different strength values and are prone to galling, so use the supplier's torque values for them.

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