Instantly calculate chipload from your feeds and speeds
Enter your parameters above
Chipload (also called "chip load" or "feed per tooth") is the thickness of material each cutting edge removes per revolution. It's the single most important number for CNC cutting—more important than RPM or feed rate alone.
For example, running at 18,000 RPM with a 100 ipm feed rate and a 2-flute bit:
The goal is to create chips thick enough to carry heat away from the cut, but not so thick that you overload the tool. Get it wrong and you'll either:
These are general guidelines for hobby CNC routers. Your specific machine, tooling, and setup may require adjustment.
| Material | Chipload Range (inches) | Notes |
|---|---|---|
| Hardwood Oak, Maple, Walnut |
0.001" – 0.003" | Start conservative. Sharp tools essential. |
| Softwood Pine, Cedar, Poplar |
0.002" – 0.004" | More forgiving. Watch for tearout on grain. |
| Plywood Baltic Birch, MDF Core |
0.001" – 0.003" | Glue is hard on tools. Use compression bits for clean edges. |
| MDF | 0.002" – 0.005" | Consistent cutting. DUST HAZARD—use good extraction. |
| Plastic Acrylic, HDPE, PVC |
0.003" – 0.007" | Higher chipload prevents melting. Single flute often best. |
| Aluminum 6061, Cast |
0.001" – 0.002" | Use cutting fluid. Ramp entry. Clear chips constantly. |
Input your spindle RPM, feed rate, and the number of flutes on your bit.
Green means you're in a good range. Yellow means caution—you might be pushing limits. Red means you're likely to have problems.
If chipload is too low, increase feed rate or decrease RPM. If too high, do the opposite.
Calculator gives you a starting point. Use our full testing tool to dial in parameters based on actual cut results.
Neither on its own. What matters is the ratio between them, which determines chipload. You can run high RPM with high feed, or low RPM with low feed, and get the same chipload.
Maybe. Manufacturer specs are often based on industrial machines with rigid frames and powerful spindles. Hobby CNCs may need lower RPM or adjusted feed rates to achieve proper chipload without causing chatter.
Fewer flutes = bigger chip clearance. Use 1-2 flutes for soft materials, plastics, and aluminum. Use 2-3 flutes for hardwoods. More flutes give smoother finish but require faster feed to maintain chipload.
Chipload is one factor. You might have issues with depth of cut, tool deflection, dull tools, or improper work holding. Use our full testing tool to diagnose based on actual cut results.
1 inch = 25.4mm. For chipload: 0.001" = 0.0254mm. The calculator handles unit conversion automatically when you switch feed rate units.
The calculator gives you a starting point. Our full testing tool helps you dial in parameters based on actual cut quality.
Start Testing Feeds & Speeds Guide