Tooling Reference
End Mill Size Chart
Standard end mill sizes in fractional inch and metric, sorted by actual cutting diameter, with the diameters we carry marked and their catalog lengths listed.
Standard End Mill Sizes, Inch and Metric
Catalog A size we carry, lengths listed Custom Ground to order Bold marks the system a size is specified in. Metric rows sit on grey.
| Inches | Metricmm | Catalog Lengths | Availability | ||
|---|---|---|---|---|---|
| Fraction | Decimal | Cutting | Overall | ||
| 1/64 | 0.0156 | 0.397 | — | — | Custom |
| ≈ 1/64 | 0.0197 | 0.5 | — | — | Custom |
| 1/32 | 0.0313 | 0.794 | — | — | Custom |
| ≈ 3/64 | 0.0394 | 1 | — | — | Custom |
| 3/64 | 0.0469 | 1.191 | — | — | Custom |
| ≈ 1/16 | 0.0591 | 1.5 | — | — | Custom |
| 1/16 | 0.0625 | 1.588 | — | — | Custom |
| 5/64 | 0.0781 | 1.984 | — | — | Custom |
| ≈ 5/64 | 0.0787 | 2 | — | — | Custom |
| 3/32 | 0.0938 | 2.381 | — | — | Custom |
| ≈ 3/32 | 0.0984 | 2.5 | — | — | Custom |
| 7/64 | 0.1094 | 2.778 | — | — | Custom |
| ≈ 1/8 | 0.1181 | 3 | 4–9 mm | 50 mm | Catalog |
| 1/8 | 0.1250 | 3.175 | 0.156–0.375 in | 2 in | Catalog |
| 9/64 | 0.1406 | 3.572 | — | — | Custom |
| 5/32 | 0.1563 | 3.969 | 0.188–0.469 in | 2 in | Catalog |
| ≈ 5/32 | 0.1575 | 4 | 5–12 mm | 50 mm | Catalog |
| 11/64 | 0.1719 | 4.366 | — | — | Custom |
| 3/16 | 0.1875 | 4.763 | 0.375–0.5625 in | 2 in | Catalog |
| ≈ 3/16 | 0.1969 | 5 | 8–15 mm | 50 mm | Catalog |
| 7/32 | 0.2188 | 5.556 | — | — | Custom |
| ≈ 1/4 | 0.2362 | 6 | 8–18 mm | 50 mm | Catalog |
| 1/4 | 0.2500 | 6.350 | 0.25–1 in | 2–3 in | Catalog |
| 5/16 | 0.3125 | 7.938 | 0.3125–1.25 in | 2–3 in | Catalog |
| ≈ 5/16 | 0.3150 | 8 | 10–24 mm | 50–64 mm | Catalog |
| 3/8 | 0.3750 | 9.525 | 0.375–1.5 in | 2.5–3 in | Catalog |
| ≈ 3/8 | 0.3937 | 10 | 14–30 mm | 65–73 mm | Catalog |
| 7/16 | 0.4375 | 11.113 | — | — | Custom |
| ≈ 1/2 | 0.4724 | 12 | 16–36 mm | 75–89 mm | Catalog |
| 1/2 | 0.5000 | 12.700 | 0.5–3 in | 3–6 in | Catalog |
| ≈ 9/16 | 0.5512 | 14 | — | — | Custom |
| 9/16 | 0.5625 | 14.288 | — | — | Custom |
| 5/8 | 0.6250 | 15.875 | 0.625–2.5 in | 4–5 in | Catalog |
| ≈ 5/8 | 0.6299 | 16 | 20–48 mm | 100–122 mm | Catalog |
| ≈ 3/4 | 0.7087 | 18 | — | — | Custom |
| 3/4 | 0.7500 | 19.050 | 0.75–3 in | 4–6 in | Catalog |
| ≈ 3/4 | 0.7874 | 20 | 25–60 mm | 100–125 mm | Catalog |
| 7/8 | 0.8750 | 22.225 | — | — | Custom |
| ≈ 1 | 0.9843 | 25 | — | — | Custom |
| 1 | 1.0000 | 25.400 | 1–4 in | 4–6 in | Catalog100, 150, 170, 190, 200 series |
| 1‑1/4 | 1.2500 | 31.750 | — | — | Custom |
| 1‑1/2 | 1.5000 | 38.100 | — | — | Custom |
| 2 | 2.0000 | 50.800 | — | — | Custom |
Cutting length and overall length span the shortest and longest offered at that diameter across every series that carries it. For one specific tool, open the series page. Sizes marked Custom are ground to order, including every diameter below 1/8" and above 1".
End Mill Dimensions Explained
Cutting diameterThe diameter across the flutes, and the number a tool is ordered by.
Cutting lengthFlute length. Sets the deepest wall a single pass can finish.
Overall lengthNose to shank end. Sets reach, and every increase costs rigidity.
Shank diameterWhat the holder grips. Often larger than the cutter on small tools. Listed per tool on the series pages.
Common End Mill Sizes by End Type
Every end type runs the same ladder from 1/8" and 3 mm up. Only square end goes to 1", and the 240 Series skips 3/16". Flute count and coating change with the material, not the size.
Square end 100 · 110 · 150 · 170 · 190 · 200 1/8" – 1" | 3 – 20 mm Ball nose 120 · 220 1/8" – 3/4" | 3 – 20 mm Rougher / profiler 100R 1/8" – 3/4" | 3 – 20 mm Chipbreaker 100C · 200C 1/8" – 3/4" | 3 – 20 mm Aluminum HSM 240 1/8" – 3/4" | 3 – 20 mm Ground to order Any diameter on the chart Reach, neck, form and coating to your print
Size Questions
What are the most common end mill sizes?
In fractional inch, 1/8", 1/4", 3/8" and 1/2" cover the majority of general machining work, with 3/16", 5/16", 5/8" and 3/4" close behind. In metric the equivalent working set is 3, 6, 10 and 12 mm. We carry all of them.
What are standard metric end mill sizes?
The standard metric ladder runs 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20 and 25 mm. We carry nine of those, 3 mm through 20 mm. Metric cutters are frequently ground on inch shanks for North American holders, so check shank diameter on the series page before ordering.
What size ball nose end mills do you make?
Ball nose runs the full catalog ladder, 1/8" through 3/4" and 3 mm through 20 mm, in our 120 Series for steel, iron, titanium and nickel alloys and our 220 Series for aluminum, copper and plastics. Larger or smaller ball nose is a custom grind.
Can I get a size that isn't in the catalog?
Yes. Every diameter on the chart marked Custom is ground to order on the same 5-axis CNC equipment used for catalog tools, along with reach, neck length, form and coating built to your print. Send the dimensions and we'll quote it.
Get the Size You Actually Need
Catalog sizes are standard production. Anything else is ground to your print on the same equipment. Send the dimensions and we'll quote it.
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