SFM Calculator: Global Machining Speed Tool
The most accurate SFM calculator for CNC, lathe, milling, and drilling — supports imperial and metric units with material-specific recommendations.
"Speed kills — but only if it's wrong." — Machinist Wisdom
How the SFM Calculator Works
Our SFM calculator uses standard formulas:
- SFM = (π × Diameter × RPM) / 12 (inches)
- SFM = (π × D_mm × RPM) / 304.8 (mm → SFM)
- RPM = (SFM × 12) / (π × D)
- π ≈ 3.14159
Understanding SFM Calculator Results
You get:
- SFM or RPM in real time
- Material safety check (Green/Yellow/Red)
- Recommended RPM range
- Metric conversion
Why Use This SFM Calculator?
Trusted by machinists worldwide:
- Imperial & Metric support
- 8+ material presets
- Real-time validation
- Safety warnings
- Mobile-optimized
Real SFM Calculator Examples
- 0.5" end mill in Aluminum @ 3000 RPM: → 392 SFM
- 10 mm drill in Steel @ 800 RPM: → 82 SFM
- 2" face mill in Cast Iron @ 400 RPM: → 209 SFM
- 1/4" bit in Wood @ 12000 RPM: → 785 SFM
Recommended SFM by Material
- Aluminum: 200–1000 SFM
- Mild Steel: 100–300 SFM
- Stainless: 80–200 SFM
- Titanium: 50–150 SFM
- Plastic: 500–1500 SFM
- Wood: 1000–3000 SFM
Metric Conversion (SFM to m/min)
1 SFM = 0.3048 m/min | 1 m/min = 3.28084 SFM
Get Started with SFM Calculator
- Enter Tool Diameter
- Select Unit (in/mm)
- Enter RPM or Choose SFM
- Select Material
- View Instant Result
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