CNC Speeds & Feeds Calculator
Start with sane feeds, RPM, and chip load for wood, MDF, and plastics. Reduce burning, avoid dust rubbing, and tune for finish quality without guessing.
- Select material and bit diameter.
- Set flute count (and chip load if adjustable).
- Start with recommended RPM and feed.
- Test cut, then tune by chips, sound, and finish.
Safe CNC Feeds & Speeds
Sets recommended surface speed (SFM) and cutting force (Kc). Harder materials → lower chipload, higher force.
Rigidity & max practical feed. Stiffer frames tolerate higher feed and deeper passes with less chatter.
Power vs RPM curve limits what cuts are sustainable. Heavier cuts need usable watts near your chosen RPM.
Geometry affects chip evacuation & finish. Downcuts/compression push chips down — favor ramping & lighter slotting.
Adjust and watch feeds update in real time. All conversions are automatic.
Larger tools carry higher chiploads & deeper DOC, but need more power and clearance in corners.
Adjust and watch feeds update in real time. All conversions are automatic.
More flutes = more cuts per rev. Great for finish at high RPM with strong chip evacuation.
Adjust and watch feeds update in real time. All conversions are automatic.
Length from collet to tip. Longer = more deflection. Keep as short as practical for rigidity.
Adjust and watch feeds update in real time. All conversions are automatic.
Width of cut per pass. Lower AE triggers chip-thinning (this calc includes that).
Adjust and watch feeds update in real time. All conversions are automatic.
Depth per pass. Leave 0 for auto based on material and bit. Reduce for hard materials or long stickout.
Adjust and watch feeds update in real time. All conversions are automatic.
Pro override (mm/tooth). 0 = auto from tool size + material + bit type + cooling.
Adjust and watch feeds update in real time. All conversions are automatic.
0 = auto from SFM & diameter (never below 10 000). Respect spindle min/max.
Enable ramping when slotting with downcuts/compression. Use helical when pocketing if CAM supports it.
Start with 🐢 Slow. If cut is quiet with healthy chips (not dust), step to ⚖️ Medium or cautiously to ⚡ Fast.
CAM previews are ready to paste — imperial first, metric in parentheses.
How to use
- Choose your material (MDF, hardwood, softwood, acrylic, etc.).
- Enter bit diameter and flute count.
- Set a conservative chip load if you want a safer start.
- Run a short test pass and tune for chip shape and finish.
Pro tips
- • Burning: usually too much RPM for the feed (or too little feed for the RPM).
- • Chatter: reduce stick-out, increase rigidity, step down, or change strategy before slowing down.
- • Plywood: prioritize shear geometry and climb/conventional choice to manage tear-out.
FAQs
Why do I get dust instead of chips?
Dust usually means the edge is rubbing instead of slicing. Increase feed, reduce RPM, or change bit geometry. Also check sharpness and runout.
Is higher feed always better?
Not always. Too high can overload the cutter or cause chatter. You want stable cutting with consistent chips, not screaming or vibrating.
What matters more, chip load or RPM?
Chip load is the steering wheel. RPM and feed are the pedals. Hit a sensible chip load, then choose RPM/feed that your machine and bit can sustain.