Spindle Speed Calculator
Calculate RPM from cutting speed (SFM) and tool diameter for milling, turning, and drilling operations.
Inputs
Results
Spindle Speed
2,292 RPM
How to Use This Calculator
- Enter the recommended cutting speed (SFM or m/min) from your tooling manufacturer's chart.
- Set the tool or cutter diameter (inches or mm).
- Review the calculated spindle speed (RPM) and equivalent metric cutting speed.
- Program this RPM into your CNC controller's speed override for the current operation.
How the result changes with Tool Diameter
| Tool Diameter | Spindle Speed |
|---|---|
| 1.21 | 947 RPM |
| 4.21 | 272 RPM |
| 7.8 | 147 RPM |
| 11 | 104 RPM |
What each input means
- Cutting Speed
- Surface feet per minute recommended for the material and tool combination.
- Tool Diameter
- Cutting tool diameter in inches.
How this is calculated
Worked example, using the default values
- Identify Input ParametersCutting Speed = 300, Tool Diameter = 0.5 = 2 input(s) provided
- Calculate Spindle SpeedSpindle Speed = r2292 = 2292
- Calculate Cutting SpeedCutting Speed91.4 = 91.4
- Calculate Tool DiameterTool Diameter12.7 = 12.7
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Feed Rate Calculator
Calculate feed rate (IPM) from chip load, number of flutes, and spindle RPM for CNC milling operations.
CNC MachiningMaterial Removal Rate Calculator
Calculate cubic inches per minute from depth of cut, width of cut, and feed rate. Estimate required spindle horsepower.
SpinningSpindle Speed Calculator
Optimal whorl size from target twist and drafting speed.
Wood TurningSpindle Turning Speed Calculator
Maximum RPM from workpiece diameter and material.
TelehealthRemote Patient Monitoring Calculator
RPM device count and cost from patient panel.
More in Manufacturing, Industrial & Coatings.