M10 drill bit size: clearance hole or tapped hole?

Use an 11 mm drill bit for a normal-clearance hole that lets an M10 bolt pass through. Choose 10.5 mm for close clearance or 12 mm for loose clearance. These are the M10 sizes in Albany County Fasteners’ metric clearance chart.

If you want to cut threads into the hole, the answer changes: a conventional M10 × 1.5 cutting tap usually needs an 8.5 mm drill, not 11 mm. Sandvik Coromant’s cutting-tap example gives that size explicitly.

M10 bolt-clearance sizes

A clearance hole is unthreaded: the bolt passes through the part and engages a nut or a threaded component beyond it.

Fit	Nominal hole diameter	When to choose it
Close	10.5 mm	Accurately aligned holes where less sideways play is wanted
Normal	11.0 mm	General-purpose assembly when no other hole size is specified
Loose	12.0 mm	Assembly needing extra allowance for adjustment or misalignment

The sizes and fit descriptions follow Albany County Fasteners’ chart; NBK’s technical table independently lists the same three M10 diameters.

For example, if you are drilling a bracket so an M10 bolt can pass through into a nut, 11 mm is the normal starting choice. If the bracket drawing or equipment instructions specify a diameter and tolerance, use those instead and check the finished hole—not just the size marked on the bit. A larger hole makes alignment easier, but it is not automatically appropriate for a load-bearing joint.

Why not use a 10 mm bit?

M10 identifies a 10 mm nominal thread diameter, not the required clearance-hole diameter. A nominal 10 mm hole provides no designed clearance around that nominal diameter. Do not rely on drill wobble to make it large enough; select the intended clearance size.

Can you use a 7/16-inch bit?

7/16 inch equals 11.1125 mm, calculated using 25.4 mm per inch. It is 0.1125 mm larger than the 11 mm normal-clearance size.

That makes it a nearby option for an ordinary, noncritical pass-through hole if the extra clearance is acceptable—not an exact substitute where the drawing controls the hole size. By comparison, 13/32 inch equals 10.31875 mm, smaller than the 10.5 mm close-clearance size.

If the bolt must screw into the hole

Check the pitch and tap type before drilling. For M10 × 1.5, 8.5 mm is the usual cutting-tap hole. Fine-pitch threads need different sizes, and forming taps must not use the cutting-tap recommendation. Follow the specific tap manufacturer’s hole requirements if they differ from a general chart.

For comparison, Haas’s roll-tap chart lists 9.3 mm for M10 × 1.5 forming taps. Haas recommends drilling and reaming, and explicitly calls the chart a starting point that may need adjustment for material, hardness and tolerance. See our M10 tap-drill guide for pitch-specific cutting and forming sizes.

If you mean an M10 masonry anchor

Neither the clearance table nor the tap size determines an anchor’s hole. Follow the exact anchor’s installation specification for diameter, depth and setting procedure. For example, Fischer specifies a 12 mm drill diameter for its EA M10 × 40 N hammerset anchor; that is product-specific, not a rule for every M10 anchor.

Once you have settled the diameter, choose the bit for the workpiece. For brackets and other metal parts, our metal drill-bit guide covers bit selection and drilling setup.