CNC Machining worked example

Milling Cycle Time at 17% allowance: a worked example

What does the result look like when allowance reaches 17%? The full calculation is worked below with real intermediate numbers. estimating milling cycle time for quoting, routing, capacity planning, or comparing alternate CNC programs

The inputs for this scenario

  • Toolpath length: 240 in (unchanged)
  • Feed rate: 80 in / min (unchanged)
  • Allowance: 17 % (raised for this scenario; the documented default is 15)

Working through the calculation

  • Applying the documented formula (Base milling cycle time = milling toolpath length รท cutting feed rate) to the inputs above produces each figure below.
  • At this operating point the engine returns 3.51 min for estimated milling cycle time, the number this scenario is built around.
  • At this operating point the engine returns 3 min for base milling cycle time.
  • At this operating point the engine returns 17 % for approach, retract, and path allowance.
  • At this operating point the engine returns 80 pieces / min for cutting feed rate.

How this compares with the baseline

  • Against the tool's baseline example, where allowance sits at 15% and the headline result is 3.45 min, this scenario comes in 1.74% above the baseline at 3.51 min.
  • A figure at this level is achievable when allowance is genuinely sustained, not just peaked for a shift. It assumes a single constant feed rate across the whole path, so it understates time for jobs with many rapid traverses, tool changes, or large feed variations between roughing and finishing passes.

Results at a glance

  • estimated milling cycle time: 3.51 min (headline result)
  • base milling cycle time: 3 min
  • approach, retract, and path allowance: 17 %
  • cutting feed rate: 80 pieces / min

Run it with your numbers

  • Every input above is editable in the live Milling Cycle Time calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.