Each line or machine gets its own card. Results update as you type, totals add up across every line, and lines are ranked by annual unplanned cost. Download CSV exports that ranking with every input and output.
What you enter per line or machine
Two settings apply to every line: production weeks per year and an improvement scenario (X%). A blank or negative entry counts as zero, both percentages are capped at 0–100%, and any entry above one billion is treated as one billion.
Manufacturing downtime cost per hour: the formulas
- Cost per unplanned hour = U × CM × (1 − rec) + n × r + rec × n × r × ot
- Cost per minute = cost per unplanned hour ÷ 60
- Weekly unplanned cost = Du × cost per unplanned hour + E × (cs + cr)
- Annual unplanned cost = weekly unplanned cost × production weeks per year
- Average stop length = Du × 60 ÷ E minutes (shown as “–” when no stops are entered)
- Availability = (PPT − Du) ÷ PPT, where planned production time PPT = Sch − Dp (“–” when PPT is zero or less, “Check hours” when the result is negative)
- Planned downtime = Dp × weeks per year, in hours, with an output value of Dp × weeks × U × CM. Shown separately, never added to cost
- Savings at X% = annual unplanned cost × X%, assuming unplanned hours and stops both fall by X%
Read the hourly formula as three costs: lost margin on output you never make up, idle crew pay (counted either way), and overtime for output you do make up. Scrap, restart and repair are charged once per stop, not per hour.
The 1.5× overtime example is the federal floor: covered, non-exempt employees must get at least time and one-half their regular rate for hours over 40 in a workweek (U.S. Department of Labor). Enter your own multiplier if yours differs.
Why planned downtime isn’t added to cost
Changeovers, preventive maintenance and sanitation are on the schedule, so the calculator doesn’t treat them as losses. It uses them to work out availability and shows their hours and output value in a separate box. For stops that could go either way, see our guide to planned vs unplanned downtime.
Worked example (hypothetical)
These are the numbers the calculator opens with, not benchmarks or client data. Example line A is scheduled 80 hours a week, with 8 planned and 5 unplanned downtime hours across 12 stops. It makes 400 units an hour at a $1.25 margin, idles 5 people at $32 an hour, makes up 25% of lost output on overtime at 1.5×, and spends $75 on scrap and restart plus $120 on repair per stop, over 50 weeks a year.
- Lost margin: 400 × $1.25 × (1 − 0.25) = $375 an hour
- Idle crew: 5 × $32 = $160 an hour
- Overtime to make up output: 0.25 × 5 × $32 × 1.5 = $60 an hour
- Cost per unplanned hour: $375 + $160 + $60 = $595, or $9.92 a minute
- Weekly: 5 × $595 + 12 × ($75 + $120) = $5,315. Annual: $5,315 × 50 = $265,750
- Average stop: 5 × 60 ÷ 12 = 25 minutes. Availability: (72 − 5) ÷ 72 = 93.1%. Planned downtime: 400 hours a year, $200,000 of output, shown separately
Example machine B comes to $540 per unplanned hour and $168,000 a year. Together the two total $433,750 a year, with line A first at 61.3% of the total, and the 20% scenario shows savings of $86,750.
Assumptions and limits
- Make-up output is assumed to take as long as the time lost, with the same crew.
- Every stop on a line carries the same scrap, restart and repair cost, so enter averages.
- Lines are priced independently: a stop that starves or blocks another line isn’t modeled, and there’s no blended cost per hour across lines.
- Costs outside these inputs, such as expedited freight or late-delivery penalties, aren’t included.
- The savings figure is a what-if, not a forecast. Amber “Check” notes flag hours that are missing or don’t add up (including more than the 168 hours in a week), unplanned hours with no stops, and an overtime share with no multiplier.
