# Feed per Tooth Calculator

Feed per tooth calculator (fz). Solve fz from feed rate and RPM, recommend fz for a material, or convert feed per tooth to mm/min. Supports IPT, mm/tooth, and full milling feed math.

## What this calculates

Feed per tooth (fz, also written IPT for inches per tooth or mm/tooth in metric) is the chip thickness each flute of an end mill removes in one revolution. It is the single most important parameter for tool life, surface finish, and cycle time in milling. Run it too high and the tool fractures; too low and the tool rubs and burns. This feed per tooth calculator solves fz from feed rate and RPM, converts feed per tooth to mm/min feed rate for metric CNC, or recommends a baseline fz for your material.

## Inputs

- **Calculation Mode** — options: Solve fz from feed rate and RPM, Feed per tooth to mm/min feed rate, Recommend fz for material
- **Spindle Speed** (RPM) — min 0 — Spindle RPM. Used in all three modes.
- **Flutes** — min 1, max 16 — Cutting edges on the end mill.
- **Feed Rate** (IPM) — min 0 — Linear feed rate. Required for solve mode.
- **Feed per Tooth** (IPT) — min 0 — Feed per tooth (fz). Required for the mm/min and cross-check modes.
- **Workpiece Material** — options: Aluminum (0.004 IPT base), Mild steel (0.002 IPT), Alloy steel 4140 (0.0015), Stainless (0.0015), Tool steel (0.001), Cast iron (0.003), Brass (0.003), Titanium (0.001), Inconel 718 (0.0008), Plastic (0.005) — Used only in recommend mode.
- **Tool Diameter** (in) — min 0 — Used in recommend mode to scale the baseline fz by tool size.

## Outputs

- **Feed per Tooth** (IPT) — Feed per tooth in inches per tooth.
- **Feed per Tooth** (mm/tooth) — Feed per tooth in millimeters per tooth.
- **Feed Rate** (IPM) — Feed rate in inches per minute.
- **Feed Rate** (mm/min) — Feed rate in millimeters per minute.
- **Feed per Revolution** (in/rev) — IPR = fz x number of flutes.

## Details

The feed per tooth formula

Feed per tooth (fz or IPT) is the chip load equation turned inside out:

  - fz = Feed rate / (RPM x flutes)

  - Equivalent: Feed rate = RPM x fz x flutes

Example: a 4-flute end mill running 3,000 RPM at 24 IPM has fz = 24 / (3000 x 4) = 0.002 IPT. In metric: 24 IPM x 25.4 = 610 mm/min, and fz = 0.051 mm/tooth. That matches a standard chip load for mild steel on a half inch end mill.

Feed per tooth to mm/min

A feed per tooth to mm min calculator takes fz (mm/tooth) and returns feed rate in millimeters per minute. The formula is mm/min = RPM x fz x flutes. For a 3-flute end mill at 8,000 RPM with fz = 0.1 mm/tooth: mm/min = 8000 x 0.1 x 3 = 2,400 mm/min. That is the F value the control sees.

Feed per tooth baselines

  
    Materialfz baseline (IPT)fz baseline (mm/tooth)
  
  
    Aluminum 60610.0040.102
    Mild steel 10180.0020.051
    Alloy steel 41400.00150.038
    Stainless 304/3160.00150.038
    Tool steel (A2, D2)0.0010.025
    Cast iron0.0030.076
    Brass0.0030.076
    Titanium Ti-6Al-4V0.0010.025
    Inconel 7180.00080.020
    Plastic (Delrin)0.0050.127
  

These are baselines for a 0.5 inch (12.7 mm) end mill. Scale 0.5x for 1/8 inch tools and 1.25x for 3/4 inch tools.

Feed per tooth calculator metric

A feed per tooth calculator metric workflow accepts both fz in mm/tooth and feed rate in mm/min. The conversion is mm/tooth = IPT x 25.4. So 0.002 IPT = 0.051 mm/tooth; 0.004 IPT = 0.102 mm/tooth. This calculator returns both units simultaneously so metric CNC programmers (Fusion 360, SolidCAM, HyperMill) can pull the value without an extra conversion step.

How to use fz in your CAM

Every modern CAM system (Fusion 360, Mastercam, HyperMill, SolidCAM, Edgecam) accepts fz in either IPT or mm/tooth and computes feed rate automatically from spindle RPM and flute count. Start at the baseline fz for your material, set an appropriate cutting speed (SFM), then let the CAM compute F. First-cut safety: program F at 80 percent of the value; listen and look at chips before dialing up.

## Frequently Asked Questions

**Q: How do I calculate feed per tooth?**

A: fz = feed rate / (RPM x number of flutes). For a 4-flute end mill at 3,000 RPM and 24 IPM: fz = 24 / (3000 x 4) = 0.002 IPT (0.051 mm/tooth). This feed per tooth calculator does the math in solve mode; the reverse mode turns fz and RPM into a mm/min feed rate.

**Q: How do I convert feed per tooth to mm/min?**

A: Use feed rate (mm/min) = RPM x fz x flutes, with fz in mm/tooth. For a 3-flute end mill at 8,000 RPM with fz = 0.1 mm/tooth: mm/min = 8000 x 0.1 x 3 = 2,400 mm/min. A feed per tooth to mm min calculator runs this in one step and returns the F value for your G-code.

**Q: What feed per tooth should I use for aluminum?**

A: A 1/2 inch carbide end mill in 6061 aluminum runs 0.004 IPT (0.102 mm/tooth) as a baseline. High-performance aluminum geometries like Destiny Diamondback push to 0.008-0.010 IPT. Smaller end mills drop: 1/8 inch is 0.002 IPT, 1/4 inch is 0.003 IPT. Larger end mills rise: 3/4 inch goes to 0.005 IPT.

**Q: Does this feed per tooth calculator work in metric?**

A: Yes, the feed per tooth calculator metric mode returns fz in mm/tooth and feed rate in mm/min alongside imperial values. Inputs accept mm/tooth and mm/min via unit toggles. European and Asian shops using Fusion 360, HyperMill, or SolidCAM can paste the metric values straight into their CAM setups.

**Q: What is the relationship between fz, chip load, and IPT?**

A: They are the same parameter under different names. fz is the Sandvik and European notation; IPT (inches per tooth) is the North American name; chip load per tooth is the shop-floor term. The value represents how much material each flute removes per revolution. Whatever the name, the formula is fz = feed rate / (RPM x flutes).

**Q: Why is feed per tooth lower for stainless than for aluminum?**

A: Stainless has lower thermal conductivity and work-hardens under heat. A heavy chip per tooth overloads the flute and generates heat that softens the cutting edge. Aluminum shears cleanly, so the flute can take a bigger chip without heat buildup. Baseline fz: aluminum 0.004 IPT, stainless 0.0015 IPT, a 2.6x difference.

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Source: https://vastcalc.com/calculators/physics/feed-per-tooth
Category: Physics
Last updated: 2026-04-08