Torquecalc.com
Bolt Tightening Torque
Formula
T = K × D × F
Metric
Inch
Bolt diameter
M1.6
M2
M2.5
M3
M3.5
M4
M5
M6
M7
M8
M10
M12
M14
M16
M18
M20
M22
M24
M27
M30
M33
M36
M39
M42
M45
M48
M52
M56
M60
M64
Bolt diameter (inch)
#1 (0.073")
#2 (0.086")
#3 (0.099")
#4 (0.112")
#5 (0.125")
#6 (0.138")
#8 (0.164")
#10 (0.190")
#12 (0.216")
1/4"
5/16"
3/8"
7/16"
1/2"
9/16"
5/8"
3/4"
7/8"
1"
1-1/8"
1-1/4"
1-3/8"
1-1/2"
1-3/4"
2"
Bolt strength class
3.6 (σy = 180 MPa)
4.6 (σy = 240 MPa)
4.8 (σy = 320 MPa)
5.6 (σy = 300 MPa)
5.8 (σy = 400 MPa)
6.8 (σy = 480 MPa)
8.8 (σy = 640 MPa)
9.8 (σy = 720 MPa)
10.9 (σy = 900 MPa)
10.9.3 (σy = 970 MPa)
12.9 (σy = 1080 MPa)
14.9 (σy = 1220 MPa)
Grade 1 (σy = 248 MPa)
Grade 2 (σy = 393 MPa)
Grade 5 (σy = 621 MPa)
Grade 5.1 (σy = 724 MPa)
Grade 5.2 (σy = 724 MPa)
Grade 8 (σy = 830 MPa)
Grade 8.2 (σy = 966 MPa)
A307 (σy = 250 MPa)
A325 (σy = 724 MPa)
A490 (σy = 896 MPa)
A354 BD (σy = 586 MPa)
A449 (σy = 724 MPa)
A574 (σy = 1034 MPa)
A2-50 (σy = 170 MPa)
A2-70 (σy = 210 MPa)
A2-80 (σy = 450 MPa)
A4-50 (σy = 170 MPa)
A4-70 (σy = 450 MPa)
A4-80 (σy = 600 MPa)
Friction factor K (lubrication)
0.25 - Dry, rusty
0.22 - Dry, galvanized
0.20 - Dry, clean steel
0.18 - Dry, cadmium plated
0.17 - Dry, phosphate coated
0.16 - Machine oil
0.15 - Engine oil
0.14 - Graphite grease
0.13 - Lithium grease
0.12 - Copper paste
0.11 - Moly grease (MoS2)
0.10 - PTFE lubricant
0.09 - Anti-seize paste
0.08 - Assembly paste
0.12 - Loctite blue
0.14 - Loctite red
0.10 - Loctite green
% of yield load
50% - Minimal
55%
60% - Conservative
65%
70% - Standard
75% - Elevated
80%
85% - Heavy-duty
90% - Maximum
Thread type
Coarse
Fine
Calculate
Recommended tightening torque
0
N·m
How to use
Automotive & DIY
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