M22 Bolt & Screw Dimensions: Diameter & Head Size

M22 screw or bolt dimensions and sizes are heavy-duty fasteners commonly used in large-scale structural engineering, marine propulsion systems, heavy truck axles, and industrial chemical processing equipment. This size has a 22.00mm nominal major diameter and is available in M22 x 2.5 for the coarse series and M22 x 1.5 for the fine series, where 2.5 and 1.5 represent 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, Heavy Hex, Socket Head), manufacturer, or material grade — always verify with the official product datasheet before use.

Thread diagram for bolt and screw depicting the major diameter, minor diameter, pitch diameter, and thread pitch
Hex head diagram
Cap head diagram
Low-cap head diagram
Button head diagram
Flat head diagram
Pan head diagram
M22 x 2.5 Screw & Bolt – DIN 13-1/ISO 68-1
Dimension Size (mm)
Min Max
Major Diameter 21.623 21.958
Pitch Diameter 20.164 20.334
Minor Diameter 18.624 19.252
Thread Pitch 2.5
Major Diameter 21.623 21.958
Pitch Diameter 20.234 20.334
Minor Diameter 18.694 19.252
Thread Pitch 2.5
M22 x 1.5 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension Size (mm)
Min Max
Major Diameter 21.732 21.968
Pitch Diameter 20.854 20.994
Minor Diameter 19.93 20.344
Thread Pitch 1.5
Major Diameter 21.732 21.968
Pitch Diameter 20.904 20.994
Minor Diameter 19.98 20.344
Thread Pitch 1.5
M22 x 2.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension Size (mm)
Min Max
Major Diameter 21.682 21.962
Pitch Diameter 20.503 20.663
Minor Diameter 19.271 19.797
Thread Pitch 2.0
Major Diameter 21.682 21.962
Pitch Diameter 20.563 20.663
Minor Diameter 19.331 19.797
Thread Pitch 2.0
M22 x 1.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension Size (mm)
Min Max
Major Diameter 21.794 21.974
Pitch Diameter 21.206 21.324
Minor Diameter 20.59 20.891
Thread Pitch 1.0
Major Diameter 21.794 21.974
Pitch Diameter 21.249 21.324
Minor Diameter 20.633 20.891
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.
Hex Socket Low Cap Head – DIN 7984
Dimension Size (mm)
MinMax
Head Diameter 32.61 33
Head Height 11.73 12
Hex Socket Size 14
Hex Socket Flat Head – DIN 7991/ISO 10642
Dimension Size (mm)
MinMax
Head Diameter 35.38 36
Head Height Not specified 13.1
Hex Socket Size 14
Hex Head – DIN 933/ISO 4017
Dimension Size (mm)
MinMax
Width Across Flats 33.38 34
Width Across Corners 37.72 Not specified
Head Height 13.785 14.215
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Frequently Asked Questions

What is the tap drill size for M22 screws or bolts?

For metric fasteners, the recommended tap drill size can be calculated using this formula: Major Diameter – Thread Pitch. For an M22 x 2.5 (Coarse), the recommended tap drill is 19.50mm. For an M22 x 1.5 (Fine), the recommended drill size is 20.50mm.

What clearance hole size is needed for an M22 screw or bolt?

For an M22 fastener, a 23.00mm drill bit is utilized for a Close Fit, a 24.00mm bit is used for a Normal Fit, and a 26.00mm 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.