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Dial In Speeds & Feeds Fast

Calculate RPM, feed rate, chip load and compensation with clear formulas. Compare scenarios quickly and stop guessing in the spindle.

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CNC Speeds & Feeds Calculator showing RPM and feed rate results

Built for Machining Reality

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RPM + Feed Rate

Get the baseline numbers quickly for milling and drilling setups.

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Chip Load Focused

Work from chip load to feed rate so parameters stay consistent.

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Chip Thinning

Apply radial chip thinning compensation for light radial engagement.

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Ball Nose Helpers

Account for effective diameter changes for ball end mills.

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Power Sanity Check

Estimate power requirements to avoid stalled cuts and chatter.

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Calculation Features

Transparent Formulas You Can Trust

See how RPM and feed rate are calculated from surface speed and chip load, so you can adjust intelligently rather than trial-and-error.

  • Surface speed → RPM
  • Chip load → feed rate
  • Metric and imperial workflows
Speeds and feeds formulas and results

Radial Chip Thinning Compensation

When radial engagement is low, effective chip thickness changes. Use compensation to keep chip load where you want it.

  • Light radial engagement
  • Practical compensated feed
  • Quick comparison vs baseline
Chip thinning compensation results

Scenario Comparison for Setup Decisions

Try different tools, materials, and engagement assumptions to converge on stable parameters for your machine and workholding.

  • Iterate quickly
  • Reduce guesswork
  • More consistent outcomes
Comparing multiple speeds and feeds scenarios

Common Questions

Most calculators assume ideal rigidity and correct chip evacuation. If you see chatter or poor surface finish, reduce chip load, verify tool stickout, and check radial engagement assumptions (chip thinning can change the “right” number).
Use it for both metric and imperial workflows. The key is to stay consistent across surface speed, tool diameter and feed outputs.
It’s a starting point and a sanity-check tool. Always validate against tool manufacturer data and your machine limits.
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