TaskJunction

Milling RPM and Feed Calculator

Milling spindle RPM and table feed from cutting speed, tool diameter, and chip load.

Inputs

Results

Spindle Speed
—
Table Feed
—
Actual Cutting Speed
—

Formula

  • n = (Vc × 1000) / (π × D)
  • Vf = fz × Z × n

About this calculator

Part of our Machining & CNC Calculators collection. Cutting speed, feeds, RPM, cycle time, and tap drill charts.

How it works

RPM comes from cutting speed and cutter diameter. Table feed equals feed per tooth times number of teeth times RPM. Actual cutting speed shows what you get after RPM is rounded to a practical machine value.

Enter your values in the inputs above and click CALCULATE. Results appear on the right without a page reload. No login and no server upload.

Worked example

25 mm cutter, 120 m/min, 0.08 mm/tooth, 4 flutes.

  1. n = 120 × 1000 / (π × 25) = 1,528 RPM
  2. Vf = 0.08 × 4 × 1,528 = 489 mm/min

Result: 1,528 RPM, 489 mm/min feed, actual Vc 120 m/min.

When to use

  • Programming CNC mill feeds and speeds
  • Checking chip load against tool vendor charts
  • Balancing surface speed and table feed for a new material

Limitations

  • Full-width slotting may need reduced fz vs peripheral milling
  • No stepover or axial depth of cut adjustment
  • Assumes sharp tool and adequate coolant/chip evacuation

FAQ

What feed per tooth should I start with?
Use your insert or end mill catalog for the material. Aluminium often allows higher fz than stainless or hardened steel.
Why does actual Vc differ slightly from target?
RPM is rounded to an integer. Actual Vc is recomputed from the dialed RPM.
Can I use this for drilling?
Use the drilling calculator instead — it uses feed per revolution (mm/rev) rather than per tooth.

Privacy and accuracy

Every calculation runs locally in your browser. Your design data never leaves your device. Results are intended for preliminary engineering work. Always verify critical designs with qualified review and applicable standards before production use.

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