M6 Bolt Size and Thread Specifications
Quick answer
M6 bolts use 6mm major diameter with 1.0mm coarse pitch and a 5.0mm tap drill in ISO coarse.
They appear across machinery, automotive brackets, and general hardware.
Use the chart below for hex size and tap drill; use the tap drill calculator for fine pitch taps.
Bolt sizing and thread specifications follow widely recognized mechanical standards used in engineering and manufacturing. Standard bolt sizing references, industrial fastener charts, and mechanical thread standards ensure compatibility, safety, and correct tool selection across applications.
M6 is one of the most common metric fastener sizes. It is used in machinery, automotive assemblies, electronics, furniture, and general hardware where a 6 mm nominal diameter and 1.0 mm coarse pitch provide a strong, widely available thread. Spanish reference: perno M6. For tap drill size, thread types, and thread identifier workflows, pair this page with tools as you verify threads.
Specifications
| Specification | Value |
|---|---|
| Nominal diameter | 6 mm |
| Standard pitch | 1.0 mm |
| Fine pitch | 0.75 mm |
| Tap drill size | 5.0 mm |
| Closest imperial equivalent | 1/4-20 |
Hex head size
| Bolt size | Hex head size |
|---|---|
| M6 | 10 mm |
Common uses
M6 bolts are common in machinery mounts, automotive brackets, electronics enclosures, furniture hardware, and structural components. They are widely stocked and compatible with standard M6 nuts and tapped holes. Cross-check loads with the bolt size chart and screw size conversion when you mix metric and inch bins.
Related tools
Related charts
M6 vs M8 bolt size
Shank diameter and pitch set tap drill, hex key, and strength for each ISO size. Compare values in the tables above with the M8 bolt size page when you resize hardware.
Use the bolt size chart when you compare hex and shank columns across sizes.
Metric vs UNC thread size
Metric threads list diameter in millimeters and pitch in millimeters per thread; UNC lists nominal inch diameter and threads per inch. They are not interchangeable—taps, dies, and gauges differ.
Read metric vs unc thread context when series labels are unclear.
Use screw size conversion when you must match stocked parts.
M6 specifications and tools
How to choose the right bolt size
Choosing the correct bolt size depends on load, material, and thread type. Larger diameters increase strength, while thread pitch affects holding force.
Use the bolt size chart to compare shank and hex dimensions before you standardize hardware.
Use tap drill size guidance when you plan tapped holes.
Use the thread identifier when stamped sizes are missing.
FAQ
What is the standard pitch for an M6 bolt?
The standard (coarse) pitch for M6 is 1.0 mm. Fine pitch M6 is 0.75 mm.
What drill size should be used for tapping M6 threads?
For M6 x 1.0 coarse thread, use a 5.0 mm tap drill. Use our Tap Drill Calculator for other pitches.
What imperial bolt is closest to M6?
1/4-20 UNC is the closest imperial equivalent to M6 in diameter and typical use.