Metric spindle speed
RPM = (vc × 1000) ÷ (π × D)vc is cutting speed in metres per minute. D is cutter diameter in millimetres.
Machining / interactive calculator
Milling Speeds & Feeds Calculator
Calculate spindle speed and feed rate from cutting speed, cutter diameter, flute count, and chip load. Switch units without losing the current values.
m/min
Use a value appropriate to the tool and material.
mm
Use effective cutting diameter where applicable.
z
Number of cutting edges engaged per revolution.
mm/tooth
Programmed feed per tooth, before special corrections.
Formula & assumptions
How the result is calculated
Imperial spindle speed
RPM = (SFM × 12) ÷ (π × D)SFM is surface feet per minute. D is cutter diameter in inches.
Table feed
Feed = RPM × z × fzz is the number of flutes or teeth. fz is programmed chip load per tooth.
What this tool does not select
Tooling data + material + setup → starting inputsThe calculator evaluates the inputs you provide. It does not choose a safe cutting speed or chip load for a specific tool, material, machine, or setup.
Production application disclaimerEducational starting point only. Verify cutting speed and chip load against current tooling data, then check spindle limits, workholding, tool stickout, coolant, machine condition, and material before production. Reduce or adjust values when the setup requires it.
Build a traceable input set before calculating
Locate the exact cutter series in the toolmaker’s data, then match the work-material grade or group, hardness range, tool diameter, coating and operation. Check whether the listed feed is per tooth or per revolution and whether it assumes a stated radial/axial engagement. Save the source or revision with the setup. A number from a different cutter family is not automatically transferable.
| Calculator input | What to verify in the source |
|---|---|
| Cutting speed Vc | Correct work material, tool grade and cutting condition |
| Cutting diameter D | Effective diameter at the active contact, when applicable |
| Effective edges z | Edges participating in the specified feed definition |
| Programmed fz | Per-tooth units and any engagement correction already applied |
Numerical example, not a cutting recommendation
Take illustrative inputs Vc = 100 m/min, D = 10 mm, z = 4 and fz = 0.05 mm/tooth. RPM = 1000 × 100/(π × 10) = 3183.0989. Feed per revolution is 4 × 0.05 = 0.20 mm/rev. Table feed is 3183.0989 × 0.20 = 636.6198 mm/min.
If the approved spindle command is 3000 RPM, preserving the same programmed chip load requires 600 mm/min, and actual cutting speed becomes 94.2478 m/min. Keeping the original 636.6198 mm/min instead would change chip load to 0.053052 mm/tooth. Recalculate the pair whenever the spindle command changes.
These inputs are not attributed to a named cutter or a real machining trial. Check radial engagement and the formula workflow next. Definitions: Sandvik milling formulas.
Content updated October 8, 2026. Sources and numerical examples are explained above; examples are not production test results. Editorial method · Report a correction.