Job Run Time and Completion Date Calculator for Production Orders
A routing says a part runs at 55 an hour. The customer wants to know when 2,400 will be done. Between those two sits OEE, setup, shift pattern and the weekend. This calculator converts quantity and rate into hours, working days and calendar days.
Your numbers
Ideal speed at 100 percent performance, from the routing or the machine nameplate.
Use availability times performance times quality. Setup is added separately, so exclude it here.
After breaks and meetings.
Your results
Assumes one uninterrupted job on one machine with no queue before it. Add queue time ahead of the job, and holiday or maintenance blocks, for a promise date.
Calendar days vs expected OEE
Sweeps Expected OEE on this job from 40 to 100, holding your other inputs fixed.
Compute completion dates from live production orders
Optional: we can show how open production orders and routings in your ERP could feed completion date estimates.
Optional. The tool and every export work without this. No spam.
How to use it
Enter the order quantity and the rated speed, then the OEE you honestly expect on this job. Use the achieved OEE of similar recent jobs, not the target. Add the setup time, pick the shift pattern and the working days per week. The result gives run hours, total machine hours, working days and a calendar estimate. Try different OEE values on the chart to see how sensitive the date is to performance.
- Use recent actual OEE for the same part family
- Keep setup out of the OEE number to avoid double counting
- Use scheduled hours after planned breaks
- Add queue time before the job separately
The formulas
Run hours = quantity / (rated speed times OEE). Total hours = run hours plus setup. Working days = total hours / (shifts times hours per shift). Calendar days = rounded up working days times 7 / working days per week. For 2,400 units at 55 an hour and 80 percent OEE the run is 54.5 hours, plus 2 setup is 56.5, which is 3.8 working days on two 7.5 hour shifts, so 4 working days or 5.6 calendar days on a five day week.
Using the result
This is the processing time of one operation on one machine. For a delivery promise, add the queue ahead of the job, the time for downstream operations, transit and any inspection hold. A common planning error is to promise a date from run time alone. Finite capacity schedulers in ERP and APS tools do this calculation per operation across all jobs, which is what makes their dates more reliable.
Common mistakes
Using the nameplate speed with no OEE adjustment is the biggest cause of late orders. The next is mixing scheduled and elapsed hours, for instance counting breaks as productive. Finally, many planners forget that quality losses mean they must run more than the order quantity, so enlarge the quantity by the expected scrap rate first.
Frequently Asked Questions
Which OEE should I use?
Use the average OEE achieved on similar jobs on the same machine, excluding setup. If you only have a target, test the date at a lower value too. Optimistic OEE is the usual reason orders ship late.
How do I allow for scrap?
Divide the order quantity by the expected yield first. If you must deliver 2,400 good units and expect 97 percent yield, enter about 2,474 as the quantity. Alternatively fold quality into OEE and keep the order quantity as the good count.
Does it handle multi operation routings?
No, it covers a single machine and operation. For a routing, run it per operation and add queue and move time between operations, or use a finite capacity scheduling tool that does this across the whole shop.
Why calendar days instead of working days?
Customers and sales order dates are calendar based. The calculator stretches working days by the days per week to give an approximate elapsed duration. Holidays and shutdowns are not included.
We can connect this logic to open production orders in your ERP so completion dates are computed from real routings, rates and recent OEE rather than standards.
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