MachiningCalcMachinist tools
MachiningCalc / End Mill Speeds & Feeds Calculator

End milling · cutting speed

End Mill Speeds & Feeds Calculator

Calculate spindle speed and feed rate for an end mill from known cutting data, then use depth and width of cut for a quick material-removal estimate.

Instant resultNo signupFormula shownReviewed Aug 2026
LIVE

Calculator

Enter the known values. Results update automatically.

Spindle speed—
Feed rate—
Material removal—
Feed / revolution—

Use tooling manufacturer data and stay within machine, tool and workholding limits. Calculated values are not a substitute for validated process parameters.

Immediate resultUpdates as inputs change
US machining unitsSFM, RPM, IPR, IPM
Formula visibleNo black-box output
Focused intentOne machining job per URL

Calculation method

Calculation

RPM = SFM × 12 ÷ (π × Cutter Diameter)IPM = RPM × Effective Flutes × Chip LoadMRR = Axial DOC × Radial WOC × IPM

Use values in the units shown by the calculator. Inputs must be positive and physically meaningful.

Cutting speed for an end mill

Cutting speed is set at the cutter circumference. Use the end mill's cutting diameter with the SFM recommended for its substrate, coating, geometry and work material. Do not carry one material value across every carbide or HSS tool.

Material group and tool geometry

Material group matters because machinability, hardness and heat behavior change the useful SFM and chip load range. Tool geometry matters just as much: flute count, helix, coating, edge preparation and chip space affect the usable feed.

How to calculate end mill feed rate

Once RPM is known, multiply it by the number of effective cutting teeth and chip load per tooth. The calculator also multiplies IPM by axial and radial engagement to estimate MRR for a rectangular cut.

What the result does—and does not—tell you

RPM and IPM are deterministic from the inputs. MRR is a volume-rate estimate. None of those outputs model chatter, tool deflection, chip thinning, spindle torque or thermal limits, so validate the programmed cut against the toolmaker's application data.

Methodology, standards and validation

MachiningCalc separates deterministic math from cutting-data recommendations. The calculator performs the geometry and unit relationships; the correct starting cutting data still depends on the tool, work material, coating, machine and setup.

Sources and methodological references

Frequently asked questions

End Mill Speeds & Feeds Calculator: common questions

How do you calculate speeds and feeds for end mills?

Calculate RPM from SFM and cutter diameter, then calculate IPM from RPM × effective flutes × chip load per tooth.

What speed should I run an end mill?

Use the toolmaker's starting SFM for the exact end mill and work material, then convert that SFM to RPM using the actual cutter diameter.

How do I calculate feed rate for a milling machine?

For conventional milling feed calculations, IPM = RPM × effective cutting teeth × chip load per tooth.

What is a tooth in a feed calculation?

It is a cutting edge that engages the work. Use the number of effective cutting teeth, not automatically every physical flute if some do not participate in the cut.

Why can the calculated feed feel too aggressive?

Manufacturer chip load may assume a different engagement, stickout, machine rigidity or toolpath. Radial chip thinning and machine dynamics can also require adjustment.