Surface Feet per Minute, the speed at which the cutting edge moves through the material, the main driver behind spindle RPM.

The thickness of material each cutting edge removes per revolution. It drives feed rate along with RPM and flute count.

Are the material presets accurate for every tool?

They're general carbide starting points. Actual optimal values shift with tool coating, machine rigidity, and the specific cut being made.

Machinist Speed & Feed Calculator

Get spindle RPM and feed rate for a mill or drill. Pick a material preset for a starting point, or enter your own numbers.

1. Cutting Parameters

Material Preset

Surface Speed (SFM)

Cutter Diameter (Inches)

Feed Per Tooth / Flute (IPT)

Number of Flutes / Teeth

Spindle Speed (RPM)

2,292 RPM

Table Feed Rate (IPM)

27.50 IPM

How Speed and Feed Work

RPM comes from the material's surface speed (SFM) and the tool's diameter: faster surface speeds or smaller tools mean higher RPM. Feed rate multiplies that RPM by how much material each tooth should remove per revolution. The material presets are general carbide starting points; actual values vary with tool coating, rigidity, and the specific operation.s govern linear forward velocity through tool chips, computing via: IPM = RPM × Chip Load (IPT) × Flute Count (N).

Worked Example

Milling aluminum with a 1/2 inch, 4-flute end mill at 600 SFM gives a spindle speed of 4,584 RPM. At a 0.005 inch chip load per tooth, that works out to 91.68 IPM feed rate.

Common Mistakes

Using a chip load meant for a small diameter tool on a much larger one; chip load generally needs to scale up with tool diameter.
Assuming SFM presets apply regardless of tool coating; coated carbide tools can often run faster than the general starting points here.
Ignoring rigidity and depth of cut; this calculator gives a starting RPM and feed, not a guarantee against chatter on a marginal setup.

Frequently Asked Questions

What is SFM?: Surface Feet per Minute, the speed at which the cutting edge moves through the material, the main driver behind spindle RPM.
What is chip load?: The thickness of material each cutting edge removes per revolution. It drives feed rate along with RPM and flute count.
Are the material presets accurate for every tool?: They're general carbide starting points. Actual optimal values shift with tool coating, machine rigidity, and the specific cut being made.

Disclaimer: This tool is provided for educational and informational tracking purposes only. Calculations generate baseline starting values derived from ideal standard raw structural tooling parameters. Real-world milling operations must dynamically adapt parameters to factor in machine structural rigidity, specific coolant types, actual alloy work-hardening characteristics, tool coatings, and radial depth-of-cut conditions. Spindle loads must be manually evaluated by a qualified machine programmer before launching high-speed CNC cutting files. The website owner assumes no liability.