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Reference Chart

End Mill Size Chart

Find the right end mill size for your CNC job. This chart covers diameters from 1/32" to 1" with flute counts, shank sizes, and best-fit materials.

Showing 22 of 22 end mills
Diameter (in) ▲ Diameter (mm) ▲ Flutes ▲ Shank Dia (in) ▲ Overall Length (in) ▲ Flute Length (in) ▲ Recommended Material ▲
1/32"0.7921/8"1-1/2"3/32"Aluminum, plastics, soft metals
1/16"1.5921/8"1-1/2"1/4"Aluminum, brass, acetal
3/32"2.3821/8"1-1/2"3/8"Aluminum, copper, plastics
1/8"3.1821/8"1-1/2"1/2"Aluminum, brass, mild steel
5/32"3.9743/16"2"9/16"Steel, stainless, titanium
3/16"4.7643/16"2"5/8"Steel, stainless steel
1/4"6.3521/4"2-1/2"3/4"Aluminum, brass, plastics
1/4"6.3541/4"2-1/2"3/4"Steel, stainless, cast iron
5/16"7.9445/16"2-1/2"13/16"Steel, stainless steel
3/8"9.5323/8"2-1/2"7/8"Aluminum, copper alloys
3/8"9.5343/8"2-1/2"7/8"Steel, tool steel, titanium
1/2"12.7021/2"3"1"Aluminum, brass, acetal
1/2"12.7041/2"3"1"Steel, stainless, Inconel
5/8"15.8845/8"3-1/2"1-1/4"Steel, cast iron, stainless
3/4"19.0543/4"4"1-1/2"Steel, tool steel, cast iron
1"25.4041"4"1-1/2"Steel, stainless, Inconel
0.039" (1mm)1.0021/8"1-1/2"3/16"Aluminum, plastics
0.079" (2mm)2.0021/8"1-1/2"1/4"Aluminum, brass, acetal
0.118" (3mm)3.0021/8"1-1/2"3/8"Aluminum, mild steel
0.197" (5mm)5.0046mm2"5/8"Steel, stainless steel
0.315" (8mm)8.0048mm2-1/2"7/8"Steel, titanium, Inconel
0.394" (10mm)10.00410mm3"1"Steel, stainless, tool steel
No end mills match your search. Try a different term or filter.

Quick Answer: What End Mill Size Should I Use?

An end mill is the rotating cutter your CNC mill uses to remove material. Pick the diameter to match your smallest feature, then match the flute count to the material: use 2 flutes for aluminum and soft metals so chips clear fast, and 3 or 4 flutes for steel and harder alloys for a smoother finish. The shank diameter must fit your collet or tool holder.

This chart lists 22 common end mills in fractional and metric sizes with: cutting diameter in inches and mm, flute count, shank diameter, overall length, flute length and the recommended material. Search by size, material or flute count, or filter by fractional or metric.

Common sizes: 1/8″ (3.18 mm) 2-flute → aluminum | 1/4″ (6.35 mm) 4-flute → steel | 3/8″ (9.53 mm) 4-flute → tool steel and titanium | 1/2″ (12.70 mm) 4-flute → stainless and Inconel | diameters range 1/32″–1″ (0.79–25.40 mm) | shank diameters 1/8–1″.

Notes on This Chart

  • Use 2-flute end mills for aluminum and soft metals. Use 4-flute for steel and harder alloys.
  • Shank diameter must match your collet or tool holder size.
  • Flute lengths shown are standard. Long-reach and stub options are also available.
  • Material recommendations are general. Always check your tooling catalog for coatings and grades.

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Frequently Asked Questions

How many flutes should my end mill have?

Use 2 flutes for aluminum and soft metals. The wide flute valleys clear chips fast. Use 3 or 4 flutes for steel and harder materials. More flutes give a smoother finish but leave less room for chips.

What shank size do I need?

The shank must fit your collet or tool holder. Most small end mills use a 1/8" or 1/4" shank. Larger end mills use 3/8" or 1/2" shanks. Always check your spindle collet size before ordering.

What is flute length vs. overall length?

Flute length is the cutting part of the tool. Overall length includes the shank. Use a flute length at least as long as your cut depth. Shorter flute lengths reduce deflection and chatter.

Should I use a fractional or metric end mill?

Match the end mill to your drawing units. If the part is in inches, use fractional sizes. If it is in millimeters, use metric. Mixing systems can cause tolerance errors on slot widths and pocket sizes.

Drilling, Taps & Holes Reference Series

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Tap Drill ChartTap Drill CalculatorDrill Bit Size ChartDrill Decimal EquivalentsEnd Mill Size ChartCountersink Chart

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