Free planning tool
This guide will help you understand chip load and how to use the accompanying calculator to optimise your CNC routing operations.
Live calculator
Work out optimum chip load and feed rates for your CNC router tools — with UK-scaled material starter bands (by tool diameter), surface-speed RPM helper, and live metric/imperial conversion.
Results
Feed = Chip load × RPM × Flutes
In range Within UK-scaled starter band — verify on scrap and tune for your machine.
Material bands derive from UK-published chipload tables (mm/tooth by cutter diameter), scaled for conservative starter feeds. Manufacturer bit data always overrides — test on scrap before production cuts.
Please note these are estimated starter setting guides only — bands are derived from UK-published chipload tables and scaled conservatively. Always verify on scrap and follow your tool manufacturer’s data.
Feed and chip load get you cutting cleanly — they do not answer whether a router pays for itself against subcontract work. Run the ROI calculator for production economics, then keep our monthly maintenance guide handy so spindle hours stay productive once the machine is earning.
How it helps
Work out optimum chip load and feed rates for your CNC router tools — with UK-scaled material starter bands (by tool diameter), surface-speed RPM helper, and live metric/imperial conversion.
Using the tool
Select material preset for UK-scaled starter chip-load band (optional).
Set tool diameter — bands scale with cutter size (defaults to 6 mm if not entered).
Pick solve mode: calculate feed rate, chip load, or RPM from surface speed.
Enter RPM, flutes, and target chip load or measured feed.
Review assessment badge against material band before running the job.
Sample calculation
Inputs
Results
Planning accuracy
Start 10–15% below calculated feed on new materials.
Increase feed in small steps while chips stay consistent.
Reduce feed if you hear chatter or see discoloured dust instead of chips.
Use the RPM helper when changing tool diameter but keeping similar surface speed.
Common questions
No. This is a planning calculator. Machine rigidity, collet condition, and tool quality all affect safe limits.
Use mm/min and mm/tooth if your control works in metric; toggle imperial for IPM and in/tooth — conversions are built in.
Presets show UK-scaled starter chip-load ranges by tool diameter and flute count — industrial tables run higher; your bit packaging is the authority.
Reference
Machine & tooling
Always check packaging or the maker’s website first.
Harder materials generally require lower chip loads.
Lighter machines may need slightly lower feeds to avoid vibration.
Dull tools require lower chip loads.
Poor clearing leads to overheating and re-cut chips.
Calculator outputs
mm/min and IPM shown together.
mm/tooth and in/tooth shown together.
m/min and SFM when tool diameter is entered.
planning estimate at 40% of calculated feed — tune per material.
Shop-floor practice
Better to increase feed than recover from a broken tool.
Unusual sounds often mean feed or RPM is wrong.
They should evacuate cleanly — not clog or turn to dust.
Log proven feeds per material and bit type.
More free tools
Work out optimum chip load and feed rates for your CNC router tools — with UK-scaled material starter bands (by tool diameter), surface-speed RPM helper, and live metric/imperial conversion.
This guide will help you understand chip load and how to use the accompanying calculator to optimise your CNC routing operations.
Chip load refers to the amount of material removed by each cutting edge (or tooth) of your router bit during one revolution. It’s a crucial factor in determining the correct feed rate and achieving good cutting results. Think of it as the “bite” each cutting-edge takes.
Why is Chip Load Important?
Correct chip load is essential for:
Using the Chip Load Calculator:
Know Your Inputs: You’ll need three pieces of information:
Use the Calculator: Enter the Spindle Speed and Number of Flutes into the calculator. You can either enter a desired chip load to calculate the required feed rate, or you can enter the feed rate to see what the actual chip load is.
Understand the Output: The calculator will give you the missing value. If you entered a chip load, it will give you the required feed rate. If you entered the feed rate, it will tell you your actual chip load.
Adjust and Test: Start with the calculated feed rate. Observe the cut. If the chips are being cleared efficiently, the cut is smooth, and the machine isn’t straining, you’re likely good. If you see issues (rough finish, broken chips, tool chatter), slightly adjust the feed rate.
Important Considerations:
Let’s say you’re using a two-flute bit, your spindle speed is 10,000 RPM, and you want a chip load of 0.1 mm/tooth. Enter 10000 for Spindle Speed, 2 for Number of Flutes, and leave the feed rate blank for the tool to calculate it. The calculator will tell you the required feed rate.
By understanding chip load and using the calculator effectively, you can significantly improve your CNC routing results, reduce tool wear, and increase your productivity.
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CNC routing parameters
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