Make to Order Promise Date and Lead Time Calculator
Sales needs a delivery date today, and planners need it to be honest. This calculator adds the time stages of a make to order job into one defensible promise.
Your numbers
Actual output versus standard, including minor stops.
Zero if material is in stock.
Your results
Assumes one operation and sequential material, queue, production and shipping. Multi operation routings need each step summed.
Calendar days to promise vs order quantity
Sweeps Order quantity from 10 to 1500, holding your other inputs fixed.
Automate promise dates from my ERP
Optional: discuss pulling routings and open orders into a promise date view.
Optional. The tool and every export work without this. No spam.
How to use it
Enter the quantity and the routing time per unit. Divide standard time by efficiency, because plants rarely hit 100 percent. Add queue time for work ahead of the job, material lead time if parts must be bought and the transit allowance. Choose how many days per week the plant runs so that working days convert into calendar days correctly.
Formula
Machine hours equal setup plus quantity times run time, divided by 60 and by efficiency. Production days divide those hours by productive hours per day. Total working days sum material, queue, production and shipping. Calendar days multiply by seven over working days per week and round up, so a five day plant turns ten working days into fourteen calendar days.
- Setup is paid once per run, not per unit
- Efficiency below 100 percent stretches run hours
- Shorter material lead time is usually the biggest lever
- Queue should reflect real backlog, not hope
Reading the chart
At low quantities the line is flat because material, queue and shipping dominate. At high quantities run time takes over and the line climbs. The kink shows the quantity where quoting a longer date is unavoidable. Use it to set standard lead time bands for sales.
Common mistakes
Teams quote from standard time without efficiency, forget that material and production can overlap only if you receive partial shipments, and ignore queue. If you overlap steps, reduce the relevant days manually. For multi step routings, run each operation and sum the production days.
Frequently Asked Questions
What efficiency should I use?
Use your measured OEE-style output versus standard over the last quarter. Many small plants run 65 to 85 percent. Using 100 percent will produce dates you cannot keep.
How do I handle multiple operations?
Run the calculator for each operation and add the production days, plus queue between operations. Alternatively sum all setup and run times into one total as an approximation.
Why are calendar days larger than working days?
Weekends and non working days pass while the job waits. A five day plant needs seven calendar days for every five working days, so the conversion factor is seven divided by five.
Can material and production overlap?
Yes if you can start with partial material. In that case lower the material days to the portion that blocks the first operation, or accept the sequential figure as a conservative promise.
If your ERP holds routings and open orders, Netray can help you calculate promise dates directly from that data.
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