Takt time starts with one honest number: how many minutes the line can actually build product in a day. New supervisors often write down the full shift length and stop there. That overstates what you have. A shift of 480 minutes never produces for 480 minutes, because people take breaks, attend the start-of-shift meeting, and clean up before they leave.
Available production time is the shift length minus every planned, scheduled interruption. Planned means it is on the schedule before the day starts. Breaks, the daily huddle, a scheduled 5S clean-down, and a planned changeover all count. Unplanned losses such as a jammed stapler, a missing parts tote, or a late operator do not get subtracted here. Those are problems to fix, not time to give away.
The reason we keep unplanned losses out is simple. If you subtract them, you build the losses into the pace and nobody ever sees them again. Keep the available time clean and let the shortfalls show up as missed output, where the team can chase them.
Standard Procedure
- 1Write down the scheduled shift length in minutes.
- 2List every planned interruption on the shift schedule: breaks, meetings, scheduled cleaning.
- 3Subtract the planned interruptions from the shift length.
- 4Convert to seconds if your cycle times are measured in seconds.
- 5Record unplanned stoppages separately as losses, not as deductions.
Lesson Summary
- ✓Only planned interruptions reduce available production time.
- ✓Unplanned losses stay visible as missed output so the team can act on them.