M2 screw or bolt dimensions and sizes are among the most widely used metric fasteners in laptop assembly, consumer drones, and PCB mounting. This size has a 2.00mm nominal major diameter and is commonly available in M2 x 0.4 for the coarse series and M2 x 0.25 for the fine series, where 0.4 and 0.25 represent the thread pitch in millimeters.
This charts is based on respective DIN and ISO standards for each head style and DIN 13-1 (coarse series), DIN 13-21 (fine series), and ISO 68-1 standards for the thread dimensions table to ensure compatibility across metric fastening applications.
Disclaimer: Actual dimensions or measurement may vary slightly depending on head style, manufacturer, material or applied tolerance class — always verify with the official product datasheet before use or buying.
M2 x 0.4 Screw & Bolt – DIN 13-1/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
1.886
1.981
Pitch Diameter
1.654
1.721
Minor Diameter
1.408
1.548
Thread Pitch
0.4
Major Diameter
1.886
1.981
Pitch Diameter
1.679
1.721
Minor Diameter
1.433
1.548
Thread Pitch
0.4
M2 x 0.25 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
1.915
1.982
Pitch Diameter
1.764
1.82
Minor Diameter
1.61
1.711
Thread Pitch
0.25
Major Diameter
1.915
1.982
Pitch Diameter
1.784
1.82
Minor Diameter
1.63
1.711
Thread Pitch
0.25
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 M2 x 0.4 and M2 x 0.25 screws or bolts?
For metric fasteners, the recommended tap drill size can be calculated using this formula: Major Diameter – Thread Pitch
Therefore, for an M2 x 0.4 screw or bolt (coarse), the recommended tap drill is 1.60mm, while for an M2 x 0.25 (fine), it is 1.75mm.
What clearance hole size is needed for an M2 screw or bolt?
For a Close Fit, a 2.20mm drill bit is utilized. For a Normal Fit, a 2.40mm bit is used, and for a Loose Fit, a 2.60mm bit is recommended to allow the fastener body to pass through the assembly without interference.
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.
