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Chip Load Calculator — Milling, Drilling & Turning Chip Load Per Tooth

Forward and Reverse Modes with Material-Specific Recommendations, Chip Thinning Correction, and MRR Output for Metal and Wood

Free chip load calculator for machinists, CNC programmers, and woodworkers. Enter your cutter diameter, number of flutes, spindle speed, and feed rate to calculate chip load per tooth in both forward mode (compute chip load from known feed rate) and reverse mode (compute feed rate from target chip load). Includes material-specific chip load recommendations for aluminum, mild steel, stainless, titanium, hardwood, softwood, plywood, and MDF. Accounts for radial chip thinning at partial-width cuts and reports material removal rate (MRR) in cubic inches per minute. Works for end mills, face mills, drills, and single-point turning tools.

Pro Tip: Most beginner machinists run too slow because they're afraid of breaking cutters. The irony is that too-low chip load causes rubbing instead of cutting, which generates heat and kills tools faster than aggressive cuts. If you're getting blue chips or your end mill is chattering, you probably need to increase feed rate, not decrease it. Aim for the recommended chip load range for your material and watch for consistent comma-shaped chips — that's the sweet spot.

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Chip Load Calculator
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How It Works

  1. Select Mode and Material

    Choose forward mode (you know your feed rate and want to check chip load) or reverse mode (you have a target chip load and need the feed rate). Then select your workpiece material to see recommended chip load ranges for that material and cutter type.

  2. Enter Cutter Parameters

    Input cutter diameter, number of flutes (teeth), and tool type (end mill, face mill, drill, or turning insert). For indexable tooling, enter the effective number of cutting edges engaged at once. The calculator adjusts recommendations based on tool geometry.

  3. Set Spindle Speed or SFM

    Enter either the spindle RPM directly or the desired surface feet per minute (SFM) and the calculator computes RPM from cutter diameter. Material-specific SFM recommendations are shown for reference.

  4. Enter Cut Parameters

    Specify axial depth of cut (DOC) and radial width of cut (WOC or stepover). The calculator uses the radial engagement ratio to apply chip thinning correction — at partial-width cuts, the geometric chip load is thinner than the programmed chip load, so the effective feed rate must be increased to maintain the target chip thickness.

  5. Review Results

    See calculated chip load per tooth (IPT), effective chip load after thinning correction, adjusted feed rate, table feed rate (IPM), and material removal rate (MRR in in3/min). Results are flagged green, yellow, or red against the recommended range for your material. Chip thinning factor and MRR help optimize roughing strategies.

Built For

  • CNC machinists verifying chip load is within the recommended range before running a new program on expensive material
  • CNC programmers computing feed rates from manufacturer-recommended chip loads for new tooling
  • Shop foremen troubleshooting premature tool failure by checking whether chip load is too low (rubbing) or too high (overload)
  • Woodworkers and CNC router operators calculating chip load for clean cuts without burning or tearout
  • Manufacturing engineers optimizing MRR for roughing operations to reduce cycle time and quoting costs
  • Apprentice machinists learning the relationship between feed rate, spindle speed, flute count, and chip load

Features & Capabilities

Forward & Reverse Modes

Forward mode calculates chip load from a known feed rate. Reverse mode calculates feed rate from a target chip load. Toggle between modes to check existing programs or build new ones from recommended values.

Material-Specific Recommendations

Built-in chip load ranges for aluminum, mild steel, 4140, stainless 304/316, titanium, Inconel, brass, hardwood, softwood, plywood, and MDF. Recommendations adjust based on cutter diameter and material hardness so you're always in the right ballpark.

Radial Chip Thinning Correction

At partial-width cuts (stepover less than 50% of cutter diameter), the actual chip is thinner than the programmed chip load. The calculator applies the geometric chip thinning factor and shows both the programmed and effective chip load so you can increase feed rate to compensate.

Material Removal Rate (MRR)

Calculates volumetric metal removal rate in cubic inches per minute from feed rate, depth of cut, and width of cut. Essential for job quoting, cycle time estimation, and comparing roughing strategies across different tool paths.

Metal & Wood Modes

Switch between metal machining and wood/CNC router modes. Wood mode includes router-specific presets (DeWalt 611, Makita RT0701C), MDF and plywood recommendations, and burn/chip-out warnings at sub-optimal chip loads.

Color-Coded Results

Chip load results are flagged green (optimal), yellow (acceptable but not ideal), or red (too high or too low) against the material recommendation table. Instant visual feedback without needing to cross-reference charts.

Frequently Asked Questions

When chip load is too low, the cutter rubs instead of cutting. This generates excessive heat, work-hardens the material (especially stainless and titanium), accelerates flank wear, and can cause built-up edge on the tool. In wood, low chip load causes burning and glazing. The fix is almost always to increase feed rate rather than decrease spindle speed, because maintaining proper SFM is also important for tool life.
Chip thinning occurs when your radial width of cut (stepover) is less than half the cutter diameter. In these partial-engagement cuts, the chip geometry is an arc rather than a straight slice, making the chip thinner than the programmed chip load. To maintain the target chip thickness, you need to increase the programmed feed rate by the chip thinning factor. This matters most in adaptive/trochoidal milling where stepover is typically 10-25% of cutter diameter.
The best source is the cutting tool manufacturer's catalog or website. Look for the chip load recommendation specific to your tool diameter, material, and coating. This calculator provides general ranges based on material type and cutter diameter as a starting point, but manufacturer data is always more specific. For carbide end mills in aluminum, typical chip loads range from 0.003-0.006 IPT for 1/4" cutters to 0.005-0.012 IPT for 1" cutters.
Chip load per tooth stays the same regardless of flute count for a given material and cutter diameter. However, the feed rate (IPM) changes because feed rate equals chip load times number of flutes times RPM. A 4-flute cutter at the same chip load runs at twice the feed rate of a 2-flute cutter. In aluminum, 2-3 flute cutters are preferred because they have larger flute valleys for chip evacuation despite the lower feed rate.
Yes. For twist drills, the chip load per cutting edge (IPR/2 for a standard 2-flute drill) follows the same concept. Enter 2 flutes for a standard drill. Recommended chip loads for drilling are generally higher than for milling because the cutting action is more favorable. For example, drilling 4140 steel might use 0.006-0.010 IPR (0.003-0.005 per flute) compared to 0.003-0.005 IPT for end milling the same material.
Disclaimer: Chip load recommendations are general guidelines based on common material and tooling combinations. Actual optimal chip load depends on machine rigidity, workholding, tool coating, coolant, and specific workpiece conditions. Always follow your cutting tool manufacturer's recommendations and start conservatively when machining unfamiliar materials. ToolGrit is not responsible for tool breakage, workpiece damage, or machine crashes resulting from calculator use.

Learn More

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Chip Load Explained: How to Calculate and Optimize Chip Load for Milling, Drilling, and Turning

Complete guide to chip load per tooth calculation for milling, drilling, and turning. Covers chip thinning, material-specific recommendations, tool diameter influence, and how to dial in the perfect feed rate.

Read Guide →

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