How do I calculate machining time for milling?

For milling: t = L / vf, where L is the total cut length in mm and vf is the table feed rate in mm/min. Include approach and overrun distances.

How do I calculate machining time for turning?

For turning: t = (L + approach) / (f × n), where L is cut length, f is feed per revolution, and n is spindle RPM.

What is approach distance?

Approach distance is the extra travel needed before the tool engages the workpiece. It includes rapid approach clearance and the tool lead-in. Typically 2–5 mm.

Does the formula account for rapid moves?

No. The machining time formula only covers cutting time. Total cycle time also includes rapid positioning, tool changes, and idle time.

How do I reduce machining time?

Increase feed rate (higher fz or more flutes), use higher cutting speeds with appropriate tooling, minimize the number of passes, and optimize tool paths.

Free Engineering Tool #208

Machining Time Calculator

Calculate cutting time for milling (t = L / vf) and turning (t = (L+approach) / (f × n)). Enter cut length and feed parameters.

t = L / vfMilling & TurningAuto-Calc

Operation

Cut Length (mm)

Approach Distance (mm)

Feed Rate (vf) (mm/min)

Number of Passes

Quick presets

Results

Total Machining Time

—

Time per Pass

—

Effective Feed

—

Milling Time

Turning Time

Example — Milling a 200 mm slot

Given: L = 200 mm, approach = 3 mm, vf = 400 mm/min, 1 pass

t = (200 + 3) / 400 = 0.508 min ≈ 30.5 sec

Machining Time Calculator | t = L / vf | Free Online Tool

Published by Nikolai Shelkovenko on February 15, 2026 February 15, 2026

Results

Milling Time

Turning Time