Machining Time Calculator for a Part or Lot
Estimate cutting time and a simple lot duration from path length, programmed feed, number of passes, per-part overhead, tool-change time, and one-time setup. The calculator keeps cutting time, per-part cycle time, and lot time separate so you can see what contributes to the estimate.
Use the result for planning or a quick comparison. A path-length calculation is not a replacement for CAM simulation or a measured production cycle.
Interactive calculator
Enter values and select Calculate.
Formula
Cutting time per part is path length × number of passes ÷ feed rate. With length in millimetres and feed in millimetres per minute, the result is minutes. Per-part cycle time adds the time entered for other operations and tool changes. Lot time is cycle time × quantity + one-time setup.
The calculator treats setup as a single lot cost. It does not multiply setup by the number of parts. Enter all time values in the same unit, minutes.
Worked example
Suppose each part has 200 mm of cutting path over three passes at 400 mm/min. Cutting time is 200 × 3 ÷ 400 = 1.5 minutes. Add 0.2 minutes for per-part handling and the estimated cycle becomes 1.7 minutes. For 20 parts with 32 minutes of lot setup, the estimate is 1.7 × 20 + 32 = 66 minutes.
Use realistic path and overhead values
Include every cut pass that follows the same path. For different tools or feeds, calculate each operation separately and add the time. Include approach and retract motion only if you have a reasonable estimate; do not hide it inside cutting feed. Add inspection, loading, clamping, deburring, and other work only when they belong in the planning question.
The estimate assumes the entered feed is constant during the full cutting path. It excludes acceleration, rapid moves unless entered as overhead, toolpath corners, chip clearing, spindle ramp-up, dwell, tool wear, and machine interruptions. A feed override, adaptive toolpath, or complex 5-axis move can change actual time.
For feed calculations, see the milling speeds and feeds calculator. Sandvik Coromant also defines machining time as machining length divided by table feed in its milling formula reference.
