M3 Screw Size Chart – Head Dimensions, Drive Sizes & Thread Pitch | Monster Bolts
M3 screw and bolt sizes are common in electronics, robotics, 3D printing, and small machinery. Use this chart to quickly find head height, head diameter, and drive size for popular M3 types. If you’re new to standards, DIN and ISO numbers are the exact identifiers that define official dimensions (e.g., DIN 912, ISO 7380). Standard coarse thread for M3 is M3-0.50.
Metric M3-0.50 (Coarse) – Dimensions & Drive Sizes
| Type | DIN | ISO | Head Height | Head Diameter | Drive Size |
|---|---|---|---|---|---|
| M3 Hex Bolts (FT) | 933 | 4017 | 2.125 mm | 6.0 mm* | 5.5 mm WAF |
| M3 Hex Bolts (PT) | 931 | 4014 | 2.125 mm | 6.0 mm* | 5.5 mm WAF |
| M3 Socket Head Cap | 912 | 4762 | 3.0 mm | 5.68 mm | 2.5 mm hex |
| M3 Low Head Socket Cap | 7984 | — | 2.0 mm | 5.5 mm | 2 mm hex |
| M3 Button Head Socket | 9427 | 7380 | 1.65 mm | 5.7 mm | 2 mm hex |
| M3 Flat Head Socket | 7991 | 10642 | 1.86 mm | 6.7 mm | 2 mm hex |
| M3 Phillips Flat Head | 965 | — | 1.65 mm | 5.6 mm | #1 Phillips |
| M3 Phillips Pan Head | 7985 | 7045 | 2.52 mm | 6.0 mm | #1 Phillips |
All of these pair with matching M3 nuts and M3 washers.
Legend: PT = Partial Thread, FT = Full Thread. * = Width Across Flats (hex).
- Metric Thread Pitch Table • US TPI (comparison)
- How to Measure Length & Diameter • Printable Ruler (to scale)
- Shop all M3 fasteners — fast shipping from Milton, Florida.
M3 FAQs
What hex key fits an M3 socket head cap screw?
Typically a 2.5 mm hex key. Low-head and button socket styles commonly use a 2 mm hex.
What nut fits an M3 screw?
M3 screws pair with M3 nuts and M3 washers. Metric fasteners always match by nominal diameter.
What is the standard M3 thread pitch?
Standard coarse pitch is M3-0.50. Fine-pitch variants exist but are less common—always verify your tapped hole or nut.
Is an M3 the same as #4-40?
M3 (~0.118" diameter) is close to #4-40 (~0.112"), but they are not interchangeable due to different diameters and thread systems.