Free Tool

Free Speeds and Feeds Calculator

Calculate RPM, feed rate, chip load, and compensation with clear formulas. Compare scenarios quickly for any material — aluminum, steel, stainless, or titanium.

Calculate Speeds & Feeds See Features
Speeds and feeds calculator showing RPM and feed rate results for CNC milling

Built for Machining Reality

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RPM & Feed Rate

Get baseline speeds and feeds quickly for milling, drilling, and facing operations from SFM and chip load.

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Chip Load Focused

Work from target chip load to feed rate so parameters stay consistent with toolmaker recommendations.

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Chip Thinning Compensation

Automatically apply radial chip thinning correction when stepover is less than 50% of tool diameter.

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Ball Nose Effective Diameter

Calculate effective cutting diameter for ball end mills based on actual depth of cut — critical for 3D finishing.

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Power & Torque Check

Estimate spindle power and torque requirements. Avoid stalled cuts and unexpected chatter from exceeding machine limits.

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No Signup Required

Runs locally in your browser. Your jobs, tools, and material setups stay completely private.

Calculation Features

Transparent Formulas You Can Verify

See exactly how RPM and feed rate are calculated from surface speed and chip load. Show Math mode reveals every step so you can validate and learn rather than blindly trust numbers.

  • Surface speed (SFM/m/min) → RPM conversion
  • Chip load × flutes × RPM → feed rate
  • Metric and imperial unit systems
  • Material-specific SFM ranges built in
Speeds and feeds formulas showing step-by-step RPM and feed rate calculation

Radial Chip Thinning Compensation

When radial engagement is less than 50% of tool diameter, the actual chip thickness decreases. This calculator compensates by increasing feed rate to maintain target chip load — preventing rubbing and premature tool wear.

  • Automatic detection of light radial engagement
  • Compensated feed rate vs nominal comparison
  • Effective chip load display
  • Critical for HEM/adaptive toolpaths
Chip thinning compensation showing increased feed rate for light radial cuts

Material Database With ISO Groups

Built-in material database organized by ISO groups (P, M, K, N, S, H). Search by name or alloy number to get recommended SFM ranges for carbide and HSS tools with various coatings.

  • 50+ materials: aluminum alloys, steels, stainless, titanium
  • ISO material group classification
  • Machinability ratings for relative comparison
  • SFM ranges for carbide and HSS
Material selection showing ISO groups and recommended cutting speeds

Speeds and Feeds FAQ

For aluminum (6061-T6) with a carbide end mill: SFM 800-1200, chip load 0.001-0.003" per tooth for 1/4" end mills (scale up for larger tools). Use the calculator to get exact RPM and feed rate for your tool diameter and flute count. Aluminum is forgiving — err on the faster side to avoid rubbing.
For 304 stainless with carbide: SFM 200-400, chip load 0.001-0.003" per tooth. Stainless work-hardens, so never rub — maintain adequate chip load. Use TiAlN-coated tools and keep radial engagement reasonable. The calculator applies appropriate chip load ranges automatically.
Chip load = Feed Rate ÷ (RPM × Number of Flutes). Target chip load is typically 1-5% of tool diameter for end mills. This calculator works the other way: you pick a target chip load from material data, and it calculates the required feed rate. This ensures consistent results.
When your stepover (radial depth of cut) is less than 50% of tool diameter, the actual chip is thinner than the programmed feed per tooth. To maintain proper chip load, you must increase feed rate by the chip thinning factor. This is critical for HEM/adaptive toolpaths where radial engagement is 10-20% of diameter.
Calculator results assume ideal rigidity, correct tool stickout, and good chip evacuation. If you see chatter or poor finish: reduce the aggressiveness slider (start at 70-80%), check tool stickout (shorter is stiffer), verify workholding, and confirm your machine spindle can handle the required power.
It is a starting point and sanity-check tool. Always cross-reference against your tool manufacturer's data sheets for recommended SFM and chip load ranges. The calculator helps you convert those recommendations into actionable RPM and feed rate numbers for your specific setup.
Both imperial (inches, SFM, IPM) and metric (mm, m/min, mm/min). Toggle between them in the interface. The calculator converts all values consistently — just stay in one unit system for your workflow.
No. Everything runs in your browser. Machine profiles and tool library save to your browser's local storage only. Nothing is uploaded to any server.

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Free. Transparent formulas. No signup needed.

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