What does an hour of downtime cost your plant?
Put in one line's rate, margin, crew and stop minutes, and see the cost per hour, per shift and per year, counted the way a plant controller would accept.
How do you calculate the cost of downtime?
Multiply the hours lost by what an hour of production is worth. If the line is the bottleneck or you're sold out, an hour is worth the margin on the parts it would have made, after material and other variable costs, plus the pay of the operators waiting for it to restart. If the parts can be made up later, the cost is the idle crew plus the overtime to catch up.
Then multiply by how often it happens. Forty-five minutes a shift sounds small; over ten shifts a week it's 360 hours a year.
- Per hour of downtime
- $768
- Per shift
- $576
- Downtime hours per year
- 360
Per hour: $540 in lost margin on 120 parts, plus $228 for the idle crew.
worth $69,120 a year on this line.
Estimates only. Nothing you enter leaves this page.
The calculator's starting numbers, step by step
A bottleneck assembly line making 120 parts an hour at a $4.50 contribution margin, with six operators at $38 an hour loaded. It loses 45 minutes a shift to unplanned stops, over ten shifts a week and 48 weeks a year.
| Step | Calculation | Result |
|---|---|---|
| Lost margin per hour | 120 parts × $4.50 | $540 |
| Idle crew per hour | 6 operators × $38 | $228 |
| Cost per downtime hour | $540 + $228 | $768 |
| Downtime hours per year | 45 min × 10 shifts × 48 weeks ÷ 60 | 360 h |
| Cost per year | $768 × 360 | $276,480 |
| A 25% reduction is worth | $276,480 × 0.25 | $69,120 a year |
If the same line had spare capacity, the 120 parts could be made up on overtime. The hourly cost becomes the idle crew ($228) plus six operators on overtime at a 50% premium ($342), or $570 an hour, $205,200 a year. That is still a large number, and it doesn't depend on assuming any lost sales.
What to count, and what not to
A downtime cost only drives decisions if finance believes it. Overcounting is the more common mistake.
Count
- Lost contribution margin, only on the constraint or a sold-out line, where the parts can't be made up
- Idle labour for the crew that can't be moved to other work
- Catch-up overtime when lost parts are made up later
- Restart scrap, the parts made while the line comes back up to quality
- Expediting and penalties: premium freight, missed-delivery charges
Don't count
- Full selling price. The material was never used, so only the margin is lost
- Lost margin on non-bottleneck machines. Their lost time can usually be recovered without losing a sale
- Fixed overhead like rent and salaried staff, which you pay whether the line runs or not
- The same stop twice. A stop that starves the next machine is one loss, not two
The input that's usually wrong: minutes per shift
This figure usually comes from operator logs, which miss the stops that last a few minutes and round off the long ones. Captured from the machine, the minutes per shift tend to come out higher. At the line above, ten unrecorded minutes a shift would be worth another $61,440 a year. Why downtime is under-reported, and how to capture it →
Downtime cost questions
- How do you calculate the cost of downtime in manufacturing?
- Work out what one hour of lost production costs, then multiply by the hours lost. On a bottleneck or sold-out line, an hour costs the contribution margin on the parts you didn't make (selling price minus material and other variable costs) plus the wages of the crew standing idle. On a line with spare capacity the lost parts can be made up later, so the cost is the idle labour plus the overtime needed to catch up. Add scrap from restarts, expediting and late-delivery penalties if they apply.
- What is the average cost of downtime in manufacturing?
- There isn't a useful average. The cost of an hour ranges from a few hundred dollars on a small cell with spare capacity to many thousands on a bottleneck assembly line, and it depends mostly on whether the lost output can be recovered. Calculating it for your own lines, with your own margins and crew sizes, gives a number people will act on.
- Should lost sales be included in the cost of downtime?
- Only when the output is lost for good: the line is the plant's constraint, or demand is higher than you can make. If the parts can be made on the next shift, count the idle labour and the catch-up overtime instead. Counting full lost sales on every machine overstates the cost and makes the number easy to dismiss.
- Why is downtime usually underestimated?
- Because it is usually measured from manual logs. Short stops of a few minutes rarely get written down, and long stops get rounded. When downtime is captured automatically from the machine, plants commonly find more of it than their logs showed, especially in stops under five minutes.
Set up around how your plant runs
Standardized platforms expect the plant to change to fit the software. Do-it-yourself platforms leave your team to build and maintain everything. With 10in6, we configure the system around your equipment, codes and reports, and your team runs it day to day.
Your equipment, codes and reports
Reason codes set per machine, stop detection from your existing PLCs (older equipment included), and reports built for the downtime review your team holds each week.
Your team runs it day to day
Operators, downtime and scrap codes, products and targets, shift schedules, checks, alerts, emailed reports and real-time boards are managed by your own people. Everyday changes need no support ticket and no invoice.
A project manager for the bigger things
New machines, new modules and custom reports go through a 10in6 project manager who already knows your deployment, so nothing starts from scratch. If you would rather we made everyday changes too, we can.
Still here years later
The system keeps being refined after go-live, and new capabilities are added without rebuilding it. Some of our customer relationships have run for 12 years, and 97% of customers say they would never go back.
“[Our 10in6 project manager] is very quick to respond if we have questions or issues. He has helped us get the information we want out of 10in6, sharing standard reports we didn’t know about, or making adjustments when needed.”
How the 10in6 delivery model works →
Swap the estimate for measured downtime.
Tell us about the line you just priced. We'll show you what automatic downtime capture would record there: every stop, its reason and its cost.
Free 30–60 minute call with one of our engineers.