M16 - Basic Thread Dimensions

Property mm Inch
Nominal Diameter 16 0.6299
Pitch (Distance) 2 0.0787
Pitch Diameter 14.701 0.5788
Minor Diameter 13.835 0.5447
Thread Height 1.083 0.0426
Addendum 0.65 0.0256
Crest (External)
Root (Internal)		 0.25 0.0098
Tap Drill Size
(75% depth)		 14.05 0.553
Lead Angle
(Single Start)		 2.48°
Thread Family Metric Coarse Pitch (MC)
Relevant Standards ISO 68-1, ISO 9651-1, ISO 965-2, ISO 261,DIN 13
Equivalent Inch Thread5/8 - 12 12-UN

For more threading data scroll down, or use the Thread Calculator

Table of Content

M16 Possible Thread Classes

External Threads

Choose tolerance class: 4g, 4h, 6e, 6g, 6h, 8e, 8g, 5g4g, 5h4h, 5g6g, 7g6g, 7h6h, 7e6e, 9e8e, 9g8g

Metric ISO External Thread - Tolerance sketch

Internal Threads

Choose tolerance class: 4H, 5H, 5G, 6H, 6G, 7H, 7G, 8G

Metric ISO Internal Thread - Tolerance sketch

M16 4g (External)

* Permisable values for thread Class 4g

# Description Value (mm) Value (Inch)
es Allowance 0.038 (Ref) 0.0015 (Ref)
d Major Diameter 15.782 - 15.962 0.6213 - 0.6284
d2 Pitch Diameter 14.563 - 14.663 0.5733 - 0.5773
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.44 0.0098 - 0.0173
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

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M16 4h (External)

* Permisable values for thread Class 4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 15.82 - 16 0.6228 - 0.6299
d2 Pitch Diameter 14.601 - 14.701 0.5748 - 0.5788
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.44 0.0098 - 0.0173
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

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M16 6e (External)

* Permisable values for thread Class 6e

# Description Value (mm) Value (Inch)
es Allowance 0.071 (Ref) 0.0028 (Ref)
d Major Diameter 15.649 - 15.929 0.6161 - 0.6271
d2 Pitch Diameter 14.47 - 14.63 0.5697 - 0.576
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.485 0.0098 - 0.0191
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

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M16 6g (External)

* Permisable values for thread Class 6g

# Description Value (mm) Value (Inch)
es Allowance 0.038 (Ref) 0.0015 (Ref)
d Major Diameter 15.682 - 15.962 0.6174 - 0.6284
d2 Pitch Diameter 14.503 - 14.663 0.571 - 0.5773
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.485 0.0098 - 0.0191
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

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M16 6h (External)

* Permisable values for thread Class 6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 15.72 - 16 0.6189 - 0.6299
d2 Pitch Diameter 14.541 - 14.701 0.5725 - 0.5788
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.485 0.0098 - 0.0191
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

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M16 8e (External)

* Permisable values for thread Class 8e

# Description Value (mm) Value (Inch)
es Allowance 0.071 (Ref) 0.0028 (Ref)
d Major Diameter 15.479 - 15.929 0.6094 - 0.6271
d2 Pitch Diameter 14.38 - 14.63 0.5661 - 0.576
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.545 0.0098 - 0.0215
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 8g (External)

* Permisable values for thread Class 8g

# Description Value (mm) Value (Inch)
es Allowance 0.038 (Ref) 0.0015 (Ref)
d Major Diameter 15.512 - 15.962 0.6107 - 0.6284
d2 Pitch Diameter 14.413 - 14.663 0.5674 - 0.5773
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.545 0.0098 - 0.0215
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 5g4g (External)

* Permisable values for thread Class 5g4g

# Description Value (mm) Value (Inch)
es Allowance 0.038 (Ref) 0.0015 (Ref)
d Major Diameter 15.782 - 15.962 0.6213 - 0.6284
d2 Pitch Diameter 14.538 - 14.663 0.5724 - 0.5773
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.46 0.0098 - 0.0181
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 5h4h (External)

* Permisable values for thread Class 5h4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 15.82 - 16 0.6228 - 0.6299
d2 Pitch Diameter 14.576 - 14.701 0.5739 - 0.5788
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.46 0.0098 - 0.0181
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 5g6g (External)

* Permisable values for thread Class 5g6g

# Description Value (mm) Value (Inch)
es Allowance 0.038 (Ref) 0.0015 (Ref)
d Major Diameter 15.682 - 15.962 0.6174 - 0.6284
d2 Pitch Diameter 14.538 - 14.663 0.5724 - 0.5773
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.46 0.0098 - 0.0181
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 7g6g (External)

* Permisable values for thread Class 7g6g

# Description Value (mm) Value (Inch)
es Allowance 0.038 (Ref) 0.0015 (Ref)
d Major Diameter 15.682 - 15.962 0.6174 - 0.6284
d2 Pitch Diameter 14.463 - 14.663 0.5694 - 0.5773
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.513 0.0098 - 0.0202
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 7h6h (External)

* Permisable values for thread Class 7h6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 15.72 - 16 0.6189 - 0.6299
d2 Pitch Diameter 14.501 - 14.701 0.5709 - 0.5788
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.513 0.0098 - 0.0202
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 7e6e (External)

* Permisable values for thread Class 7e6e

# Description Value (mm) Value (Inch)
es Allowance 0.071 (Ref) 0.0028 (Ref)
d Major Diameter 15.649 - 15.929 0.6161 - 0.6271
d2 Pitch Diameter 14.43 - 14.63 0.5681 - 0.576
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.513 0.0098 - 0.0202
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 9e8e (External)

* Permisable values for thread Class 9e8e

# Description Value (mm) Value (Inch)
es Allowance 0.071 (Ref) 0.0028 (Ref)
d Major Diameter 15.479 - 15.929 0.6094 - 0.6271
d2 Pitch Diameter 14.315 - 14.63 0.5636 - 0.576
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.584 0.0098 - 0.023
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 9g8g (External)

* Permisable values for thread Class 9g8g

# Description Value (mm) Value (Inch)
es Allowance 0.038 (Ref) 0.0015 (Ref)
d Major Diameter 15.512 - 15.962 0.6107 - 0.6284
d2 Pitch Diameter 14.348 - 14.663 0.5649 - 0.5773
R Root Radius 0.25 (Min) 0.0098 (Min)
C Root Truncation 0.25 - 0.584 0.0098 - 0.023
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 4H (Internal)

* Permisable values for thread Class 4H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 13.835 - 14.071 0.5447 - 0.554
D2 Pitch Diameter 14.701 - 14.833 0.5788 - 0.584
D Major Diameter 16 (Min) 0.6299 (Min)
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 5H (Internal)

* Permisable values for thread Class 5H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 13.835 - 14.135 0.5447 - 0.5565
D2 Pitch Diameter 14.701 - 14.871 0.5788 - 0.5855
D Major Diameter 16 (Min) 0.6299 (Min)
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 5G (Internal)

* Permisable values for thread Class 5G

# Description Value (mm) Value (Inch)
EL Allowance 0.038 (Ref) 0.0015 (Ref)
D1 Minor Diameter 13.873 - 14.173 0.5462 - 0.558
D2 Pitch Diameter 14.739 - 14.909 0.5803 - 0.587
D Major Diameter 16 (Min) 0.6299 (Min)
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 6H (Internal)

* Permisable values for thread Class 6H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 13.835 - 14.21 0.5447 - 0.5594
D2 Pitch Diameter 14.701 - 14.913 0.5788 - 0.5871
D Major Diameter 16 (Min) 0.6299 (Min)
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 6G (Internal)

* Permisable values for thread Class 6G

# Description Value (mm) Value (Inch)
EL Allowance 0.038 (Ref) 0.0015 (Ref)
D1 Minor Diameter 13.873 - 14.248 0.5462 - 0.5609
D2 Pitch Diameter 14.739 - 14.951 0.5803 - 0.5886
D Major Diameter 16 (Min) 0.6299 (Min)
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 7H (Internal)

* Permisable values for thread Class 7H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 13.835 - 14.31 0.5447 - 0.5634
D2 Pitch Diameter 14.701 - 14.966 0.5788 - 0.5892
D Major Diameter 16 (Min) 0.6299 (Min)
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 7G (Internal)

* Permisable values for thread Class 7G

# Description Value (mm) Value (Inch)
EL Allowance 0.038 (Ref) 0.0015 (Ref)
D1 Minor Diameter 13.873 - 14.348 0.5462 - 0.5649
D2 Pitch Diameter 14.739 - 15.004 0.5803 - 0.5907
D Major Diameter 16 (Min) 0.6299 (Min)
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

M16 8G (Internal)

* Permisable values for thread Class 8G

# Description Value (mm) Value (Inch)
EL Allowance 0.038 (Ref) 0.0015 (Ref)
D1 Minor Diameter 13.873 - 14.473 0.5462 - 0.5698
D2 Pitch Diameter 14.739 - 15.074 0.5803 - 0.5935
D Major Diameter 16 (Min) 0.6299 (Min)
LE Normal Length of Engagement 8 - 24 0.315 - 0.9449

* Back to Thread Class Selection

Tap Drill Sizes for M16

  • If not specified, assume a thread depth of 75%.
  • You can learn more about thread depth in tapping here.
  • To get the tap drill size in other depths, use our Tap Drill Size Calculator .
Thread Depth Tap Drill Size (Inch) Tap Drill Size (mm)
55% 0.574 14.57
60% 0.569 14.44
65% 0.563 14.31
70% 0.558 14.18
75% 0.553 14.05
80% 0.548 13.92
85% 0.543 13.79

Over Wire Measurements for M16


* OverWire is a measuring method to obatin the pitch diameter of threads. It is mostly used when a manufacturer does not have a Go/Nogo gauge for a thread. You can learn more about it here

mm Inch
Permissible Wire Diameter Range 1.01 - 2.021 0.0398 - 0.0796
Ideal Wire Diameter 1.155 0.0455
Possible Wires
From Standard Sets		 * 1.01
* 1.155
* 1.443
* 1.732
* 2.021
 * 0.0642
* 0.0722
* 0.077

Once you knoe your wire diameter, you need to find out what is the premissable Measurement for your pitch diameter (Depending on the class). Use our Over Wire Calculator to find out!


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