Router Bit Speed Calculator

Dial in bits for edges and trims. Compare materials, flutes, and units with clear guidance. Download a PDF report for your workshop notebook later.

Calculator Inputs
Use this for planter boxes, raised beds, trellises, and edging.
Switching units converts display labels only.
Pick the input you know best.
Ranges are conservative for common routers.
Profiles reduce chip load for complex cutters.
Large bits prefer lower RPM.
Typical routers run 8,000–24,000 RPM.
More flutes usually need slower feed.
Start low for unknown bits and materials.
Use steady motion to avoid burn marks.
For safety, split deeper cuts into passes.
More passes reduce load and tear-out.
Used only for a rough load check.
Accounts for losses and imperfect technique.
Saved into CSV and PDF exports.
Tip: If the cut burns, increase feed slightly or reduce RPM. If the cut chatters, reduce depth per pass.
Example Data Table
Typical starting points for garden-wood edging and trim.
Material Bit Diameter RPM Flutes Chip load Feed rate Notes
Softwood Spiral upcut 1/4 in 20,000 2 0.0030 in 120 in/min Good for dadoes in planter sides.
Hardwood Straight 1/2 in 16,000 2 0.0025 in 80 in/min Edge cleanup for garden bench slats.
Plywood Compression 1/2 in 18,000 2 0.0020 in 72 in/min Reduces tear-out on both faces.
These are starting values. Always follow the bit maker’s limits.
Formula Used
Core relationships used by the calculator.
  • Surface speed (SFM) = (π × Diameter(in) × RPM) / 12
  • Feed rate (in/min) = RPM × Flutes × ChipLoad(in/tooth)
  • Chip load (in/tooth) = FeedRate / (RPM × Flutes)
Metric values are converted for display.
How to Use This Calculator
A practical workflow for garden builds.
  1. Select units, material, and bit type.
  2. Enter diameter, RPM, and flute count.
  3. Choose a mode: chip load or feed rate.
  4. Set depth and number of passes for safety.
  5. Press Calculate to see results above the form.
  6. Export CSV or PDF to save your setup notes.
For large profile bits, reduce RPM and take shallow passes.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.