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 7 Nm (5.16 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.

M5 is commonly used in bicycles, motorcycles, general machinery. It is one of the most popular sizes in its category.

What is the closest imperial size to M5?

The closest imperial size to M5 is approximately ~#10-24, though they are not exactly interchangeable.

Home › Metric Bolts › M5

M5 bolt size

8 mm wrench

across-flats spanner / socket size for M5

M5 bolt — Bicycles, motorcycles, general machinery.

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	7 Nm (5.16 ft·lb)
Closest other-system size	~#10-24

🔧 Torque unit converter

Newton-metres (Nm) Foot-pounds (ft·lb) Inch-pounds (in·lb)

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

Bicycles, motorcycles, general machinery.

A 4.2 mm tap drill is correct for M5 coarse thread. The standard clearance hole is 5.5 mm.

M5 is part of the ISO metric coarse thread series, defined in ISO 261. The wrench size 8 mm is measured across the flats of the hex head.

Common applications

M5 bolts are widely used in:

Bicycles, motorcycles, general machinery
General machinery and equipment assembly
Automotive components and repairs
Structural connections (when specified by engineer)
Furniture and fixture assembly

Material and grade information

The typical grade for M5 is 8.8. This indicates:

Property class 8.8: Medium carbon steel, quenched and tempered
Tensile strength: 800 MPa minimum
Yield strength: 640 MPa minimum (0.2% proof stress)
Common coatings: Zinc plated, hot-dip galvanized, or plain

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 7 Nm (5.16 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.
What is M5 used for?: M5 is commonly used in bicycles, motorcycles, general machinery. It is one of the most popular sizes in its category.
What is the closest imperial size to M5?: The closest imperial size to M5 is approximately ~#10-24, though they are not exactly interchangeable.