M12 screw or bolt dimensions and sizes are robust fasteners used in automotive suspension systems, heavy machinery assembly, structural steel joints, and industrial piping flanges. This size has a 12.00mm nominal major diameter and is available in M12 x 1.75 for the coarse series, M12 x 1.5 for the fine series, and M12 x 1.25 for the extra fine series, where the decimal represents the thread pitch in millimeters. This reference chart follows respective DIN and ISO standards for each head style and DIN 13-1 (coarse), DIN 13-21 (fine), and ISO 68-1 standards for thread dimensions to ensure global compatibility.
Disclaimer: Actual dimensions and tolerances may vary slightly depending on head style (e.g., Hex Head, Socket Head Cap Screw, Flange Bolt), manufacturer, or material grade — always verify with the official product datasheet before use.
M12 x 1.75 Screw & Bolt – DIN 13-1/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
11.701
11.966
Pitch Diameter
10.679
10.829
Minor Diameter
9.601
10.072
Thread Pitch
1.75
Major Diameter
11.701
11.966
Pitch Diameter
10.734
10.829
Minor Diameter
9.656
10.072
Thread Pitch
1.75
M12 x 1.5 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
11.732
11.968
Pitch Diameter
10.854
10.994
Minor Diameter
9.93
10.344
Thread Pitch
1.5
M12 x 1.25 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
11.76
11.972
Pitch Diameter
11.028
11.16
Minor Diameter
10.258
10.619
Thread Pitch
1.25
Major Diameter
11.76
11.972
Pitch Diameter
11.075
11.16
Minor Diameter
10.305
10.619
Thread Pitch
1.25
M12 x 1.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
11.794
11.974
Pitch Diameter
11.206
11.324
Minor Diameter
10.59
10.891
Thread Pitch
1.0
Major Diameter
11.794
11.974
Pitch Diameter
11.249
11.324
Minor Diameter
10.633
10.891
Thread Pitch
1.0
Major Diameter –
The largest diameter of the external thread, measured crest to crest.
This defines the nominal size (e.g., M12 which is 12 mm of nominal major diameter).
Pitch Diameter –
The diameter of an imaginary cylinder where the thread thickness equals
the space between threads. This is the critical dimension for thread fit
(Tolerance classes 2A/3A for Imperial; 6g/4g6g for Metric).
Minor Diameter –
The smallest diameter of the external thread, measured root to root.
This represents the core strength of the fastener and is the theoretical
maximum diameter of the tap drill.
Thread Pitch –
The distance from a point on one thread to the corresponding point on the next.
What is the tap drill size for M12 screws or bolts?
For metric fasteners, the recommended tap drill size can be calculated using this formula: Major Diameter – Thread Pitch. For an M12 x 1.75 (Coarse), the recommended tap drill is 10.25mm (often used with a 10.2mm or 10.3mm bit depending on material). For an M12 x 1.5 (Fine), the drill size is 10.50mm, and for an M12 x 1.25 (Extra Fine), it is 10.75mm.
What clearance hole size is needed for an M12 screw or bolt?
For an M12 fastener, a 13.00mm drill bit is utilized for a Close Fit, a 14.00mm bit is used for a Normal Fit, and a 15.00mm bit is recommended for a Loose Fit. A Normal Fit is the industry standard to ensure the bolt shank passes through the assembly without binding while maintaining structural alignment.
What is the difference between a bolt and a screw?
The difference is based on the intent of the fastener’s use; If the primary intent is for the fastener to pass through an unthreaded hole and be assembled with a nut, it is a Bolt. In this application, you usually hold the head and turn the nut to apply tension. But if the primary intent is for the fastener to be installed into a threaded (tapped) hole, it is a Screw. In this application, the connection is tightened by turning the head of the fastener itself.
