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M5 bolt size
8 mm wrench
across-flats spanner / socket size for M5
M5 bolt — bikes, furniture and electronics mounts.
Full specification
| System | Metric coarse |
| Nominal diameter | 5 mm |
| Thread pitch | 0.8 mm |
| Wrench / spanner (across flats) | 8 mm |
| Tap drill | 4.2 mm |
| Clearance hole | 5.5 mm |
| Common grade / class | 8.8 |
| Typical torque | 6 Nm (4.4 ft·lb) |
| Closest other-system size | ~#10 imperial |
🔧 Torque unit converter
Pre-filled with the typical torque for M5 (8.8, dry). Edit any field to convert.
⚠️ Torque values here are general references for 8.8 on clean, dry threads. Lubrication, coatings, and the joint material change the figure significantly. For structural, automotive, or safety-critical work, always use the torque specified by the manufacturer or engineer.
About M5
M5 is widely used in bicycles, flat-pack furniture and electronic mounts.
Many bike components are M5 — a 4 mm hex key and torque spec prevent stripped alloy parts.
Frequently asked questions
- What size wrench or spanner fits M5?
- M5 bolt uses a 8 mm wrench or spanner, measured across the flats of the hex head.
- What is the torque for M5?
- A typical tightening torque for M5 bolt in 8.8 on dry threads is about 6 Nm (4.4 ft·lb). Always confirm against the manufacturer spec for important joints.
- What thread pitch and tap drill does M5 use?
- M5 bolt has a thread pitch of 0.8 mm and uses a 4.2 mm tap drill, with a 5.5 mm clearance hole.