Milling speed & feed calculator
Spindle speed from cutter diameter and material, table feed from your chip load — the two numbers every milling job starts with.
Speed and feed belong together
The spindle speed comes from the cutting speed and the cutter diameter: n = (Vc × 1000) / (π × Ø). But rpm alone says nothing about how fast to move the table — that's the feed: Vf = fz × z × n, where fz is how thick a chip each tooth takes and z the number of teeth. Spinning fast while feeding too slowly rubs and burns the cutter; feeding too fast overloads it. The pair is what matters.
Which tooling do the default speeds assume?
Solid carbide end mills — calibrated against a real reference point (aluminium, 3 mm end mill at 18 000 rpm ≈ Vc 170 m/min). For HSS cutters, roughly halve the cutting speed: just edit the Vc field.
What chip load (fz) should I use?
Small cutters take small chips: as a rough guide, fz ≈ 0.5–1% of the cutter diameter (a 6 mm end mill: 0.03–0.06 mm per tooth). Manufacturers publish exact values per cutter — those always win.
Are these values safe to use directly?
They are starting values for rigid setups with cooling. Long overhangs, deep slots and thin walls warrant slower, lighter cuts. Respect your machine's spindle and feed limits.
Is my data sent anywhere?
No — this runs entirely in your browser with plain JavaScript. Nothing is uploaded.
