RPM = (SFM × 12) / (π × Tool Diameter in inches) or RPM = (Vc × 1000) / (π × D in mm)

Feed = RPM × Chip Load × Number of Flutes

AutoEngCalc - Engineering Calculators

CNC Feed & Speed Calculator

Calculate optimal spindle RPM, feed rate and chip load for milling, turning and drilling. Built-in material SFM database for steel, aluminum, brass, plastics and more.

Spindle RPM

8000 RPM

Aluminum, 10mm end mill, SFM=300

CNC Machining Parameters

Featured: RPM • Feed Rate • Chip Load • Material SFM

Operation

Workpiece Material SFM in parentheses

Tool Diameter (mm)

Number of Flutes

Chip Load (mm/tooth) - optional Leave blank for auto

Units

Recommended Range

Safe operating window

Key Formulas

RPM = (SFM × 12) / (π × D_inch) or (Vc × 1000) / (π × D_mm)
Feed Rate = RPM × Chip Load × Flutes
Chip Load = Feed / (RPM × Flutes)

Enter parameters to see optimal speeds

CNC Guidelines

Typical SFM Values

Aluminum: 200–400 m/min

Mild Steel: 100–200 m/min

Stainless: 50–120 m/min

Chip Load Guide

Roughing: 0.1–0.3 mm/tooth

Finishing: 0.05–0.15 mm/tooth

Reduce for hard materials

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