M4 Bolt Size and Thread Specifications

M4 is a common small metric fastener used in machinery, automotive trim, electronics, and general hardware. A 4 mm nominal diameter with 0.7 mm pitch offers a good balance of strength and compact size.

Specifications

SpecificationValue
Nominal diameter4 mm
Standard pitch0.7 mm
Tap drill size3.3 mm
Closest imperial equivalent#8-32

Hex head size

Bolt sizeHex head size
M47 mm

Common uses

M4 bolts are used in machinery, automotive assemblies, electronics, furniture hardware, and light structural components. They are widely available and easy to source.

Related tools

Related charts

FAQ

What is the standard pitch for an M4 bolt?

The standard pitch for M4 is 0.7 mm.

What drill size should be used for tapping M4 threads?

For M4 x 0.7 thread, use a 3.3 mm tap drill.

What imperial screw is closest to M4?

#8-32 is the closest imperial equivalent to M4.