Metric Bolt Torque

The tightening torque is the force used to tighten the metric fasteners during assembly with a tool. This torque is transmitted to the metric fasteners using an adjustable, suitable torque wrench. The corresponding values for the various screw sizes and strength classes for metric coarse threads can be found in the metric torque table below.

The following table shows the tightening torque for metric thread fasteners. In the List metric bolt torque chart you find the metric torque unit in Nm and ft lbs. You can also made an conversion from the unit Nm to ft lbs and also from ft lbs to Nm. Please find all technical information in the following metric bolt torque chart.

5.6 Strehngth class - Aluminium screws

6.8 Strehngth class - V2A screws

8.8 Strehngth class - Titanium screws

Metric Bolt Torque Chart

In the following table of torque specifications, you will find all the necessary torque values in Newton-meters (Nm) for common screw thread sizes and strength classes. Please note that the required torque may vary due to differences in screw strength classes and thread sizes.

		Recommended mertic metric bolt torque tightening torque (Nm) tightening torque (ft lbs)
Metric Thread size
Metric Strength class	Torque Unit	4.6	5.6	6.8	8.8	10.9	12.9
M2	Nm	0,13	0,16	0,26	0,35	0,49	0,59
M2	ft lbs	0,10	0,12	0,19	0,26	0,36	0,44
M2,5	Nm	0,27	0,34	0,54	0,72	1,01	1,21
M2,5	ft lbs	0,20	0,25	0,40	0,53	0,74	0,89
M3	Nm	0,48	0,60	0,96	1,28	1,80	2,16
M3	ft lbs	0,35	0,44	0,71	0,94	1,33	1,59
M4	Nm	1,12	1,39	2,23	2,97	4,18	5,02
M4	ft lbs	0,83	1,03	1,64	2,19	3,08	3,70
M5	Nm	2,26	2,83	4,52	6,03	8,48	10,18
M5	ft lbs	1,67	2,09	3,33	4,45	6,25	7,51
M6	Nm	3,84	4,80	7,69	10,25	14,41	17,29
M6	ft lbs	2,83	3,54	5,67	7,56	10,63	12,75
M7	Nm	5,13	6,42	10,27	13,70	19,25	23,10
M7	ft lbs	3,78	4,74	7,57	10,10	14,20	17,04
M8	Nm	9,35	11,69	18,70	24,93	35,06	42,07
M8	ft lbs	6,90	8,62	13,79	18,39	25,86	31,03
M10	Nm	18	23	37	49	70	83
M10	ft lbs	13	17	27	36	52	61
M12	Nm	32	40	65	86	121	146
M12	ft lbs	24	30	48	63	89	108
M14	Nm	52	65	104	138	194	233
M14	ft lbs	38	48	77	102	143	172
M16	Nm	81	101	161	215	302	363
M16	ft lbs	60	74	119	159	223	268
M18	Nm	112	139	222	296	417	500
M18	ft lbs	83	103	164	218	308	369
M20	Nm	157	197	315	420	590	709
M20	ft lbs	116	145	232	310	435	523
M22	Nm	215	269	430	574	807	968
M22	ft lbs	159	198	317	423	595	714
M24	Nm	272	340	544	726	1020	1224
M24	ft lbs	201	251	401	535	752	903
M27	Nm	400	500	800	1067	1500	1800
M27	ft lbs	295	369	590	787	1106	1328
M30	Nm	542	677	1083	1445	2032	2438
M30	ft lbs	400	499	799	1066	1499	1798
M33	Nm	739	923	1477	1969	2770	3323
M33	ft lbs	545	681	1089	1452	2043	2451
M36	Nm	948	1185	1896	2528	3555	4266
M36	ft lbs	699	874	1398	1865	2622	3146
M39	Nm	1229	1536	2457	3276	4607	5529
M39	ft lbs	906	1133	1812	2416	3398	4078
M42	Nm	1519	1899	3038	4050	5696	6835
M42	ft lbs	1120	1401	2241	2987	4201	5041
M45	Nm	1898	2373	3796	5062	7118	8541
M45	ft lbs	1400	1750	2800	3734	5250	6299
M48	Nm	2282	2853	4565	6086	8559	10271
M48	ft lbs	1683	2104	3367	4489	6313	7575
M52	Nm	2954	3692	5907	7876	11076	13292
M52	ft lbs	2179	2723	4357	5809	8169	9804
M56	Nm	3672	4591	7345	9793	13772	16526
M56	ft lbs	2708	3386	5417	7223	10158	12189
M60	Nm	4582	5728	9164	12219	17183	20619
M60	ft lbs	3379	4225	6759	9012	12673	15208
M64	Nm	5536	6920	11071	14762	20759	24911
M64	ft lbs	4083	5104	8166	10888	15311	18373
M68	Nm	6720	8400	13440	17919	25199	30239
M68	ft lbs	4956	6196	9913	13216	18586	22303

* All information without guarantee.

What is torque?

Torque is a physical quantity that describes the strength of the rotational force applied to an object.

Torque - Unit

The unit for torque M is obtained by multiplying the unit Newton for force F by the unit meter for the lever arm r.

[M] = 1 Nm

Hence, the unit is called Newton-meter.

Formula for Screw Torque (Torque Calculation)

Torque M is obtained by multiplying the force F, which acts perpendicular to a lever arm, by the length r of the lever arm.

[M] = F ⋅ r

Example: 1 Nm (Newton-meter)

Torque is measured in Newton-meters (Nm). 1 Nm is equivalent to when a force of 1 Newton is applied with a lever arm of 1 meter, resulting in 100 grams of force.

Strength classes of screws

Screws are marked with different strength classes so that it is very easy to determine the tensile strength (Rm) and the yield strength (Re).

Example: Tensile strength class 5.6

1. Determination of Rm:

Multiply the first number by 100 to obtain the tensile strength (Rm).

=> Rm = 5 x 100 = 500 N/mm²

2. Determination of Re:

The first number is multiplied by the second number and the result is

multiplied by 10 gives the yield strength (Re).

=> Re = ( 5 x 6 ) x 10 = 300 N/mm²

	Strength classes of screws
	4.6	5.6	6.8	8.8	10.9	12.9
Tensile strength (Rm)	400	500	600	800	1000	1200
Yield strength (Re)	240	300	480	640	900	1080

* All information without guarantee.

Preload forces for screw connections

In a screw connection, two or more parts are joined together. The preload force is the force exerted by a screw or screw connection on the components. If the preload force is high enough and the screw connection is selected correctly, the screwed parts behave like one part and are therefore firmly connected.

Preload forces for regular threads

	Preload force Table for regular threads Preload force in (N)
Thread size
Strength classes	4.6	5.6	6.8	8.8	10.9	12.9
M2	338	422	675	901	1267	1520
M2,5	563	703	1125	1500	2110	2532
M3	845	1056	1689	2253	3168	3801
M4	1463	1829	2927	3902	5487	6585
M5	2395	2994	4790	6387	8982	10778
M6	3379	4224	6758	9011	12671	15205
M8	6202	7753	12404	16539	23258	27909
M10	9876	12345	19752	26336	37034	44441
M12	14400	18000	28801	38401	54001	64801
M14	19775	24719	39551	52734	74158	88989
M16	27221	34027	54443	72591	102080	122497
M18	33078	41347	66155	88207	124041	148850
M20	42534	53167	85067	113423	159501	191401
M22	53175	66469	106350	141800	199406	239288
M24	61248	76560	122497	163329	229681	275617
M27	80670	100837	161339	215119	302512	363014
M30	98027	122533	196054	261405	367600	441120
M33	122241	152801	244482	325976	458404	550084
M36	143413	179266	286826	382434	537798	645358
M39	172420	215525	344839	459786	646574	775888
M42	197407	246758	394813	526417	740275	888329
M45	231206	289007	462412	616549	867022	1040426
M48	280008	325010	520015	693354	975029	1170035
M52	312056	390070	624112	832149	1170209	1404251
M56	359643	449804	719689	959581	1349411	1619293
M60	420651	525813	841301	1121735	1577440	1892928
M64	475860	594825	951720	1268960	1784476	2141371
M68	545427	681784	1090855	1454473	2045353	2454423

* All information without guarantee.

FAQ - Frequently Asked Questions

When does a screw break?

A screw can break when the allowable yield point is exceeded, causing it to deform and ultimately leading to the screw breaking.

What can happen if the torque is too high?

Excessive torque can damage threads and components, leading to malfunctions and safety risks. Therefore, proper torque application is crucial.

How tight should you tighten wheel nuts?

The recommended torque for wheel nuts of a vehicle can be found in the vehicle's manual and is typically between 80 and 160 Newton-meters.

How much Nm is hand-tight?

Hand-tight typically corresponds to a torque of approximately 30 Newton-meters (Nm) when manually applied with a standard screwdriver or similar tool.

Where can you find torque specifications?

Torque specifications for screws and components are usually available in the manufacturer's documentation or the vehicle's manuals. If you cannot find them there, you can look up the corresponding torque for the screw in a torque specification table.