Supplier Delay Stockout Exposure Calculator
A supplier emails that your order will be a week late. Is that a problem? This calculator answers by comparing the days of coverage you have with the new receipt date and valuing any gap.
Your numbers
Exclude quarantine and stock allocated to other work.
Part of on hand you would normally not touch.
Expedite premium, idle labor or lost margin per unit of shortage.
Your results
Assumes steady usage and that the full PO quantity arrives on the new date. Partial shipments and demand changes are not modeled.
Days short vs supplier delay
Sweeps Supplier delay from 0 to 30, holding your other inputs fixed.
Late PO shortage alerts
Optional: we can build a daily alert of late purchase orders ranked by shortage exposure.
Optional. The tool and every export work without this. No spam.
How to use it
Enter usable on-hand stock, daily usage, the original due date as days from today and the slip. Add safety stock if you want to see how many days it would cover, and a cost per unit short for an estimate of exposure. The slider shows the effect of different slips on days short.
- Net out allocations and quarantined stock
- Use consumption, not forecast, if the two differ
- Update daily usage when the build schedule changes
The method
Coverage in days is on hand divided by daily usage. Days short is the receipt date minus coverage, floored at zero. Compare the original and delayed receipts to isolate the harm caused by the delay. Units short is days short times daily usage, which is also the minimum quantity you would need to expedite from another source.
Reading the result
If the delayed receipt still falls inside your coverage, no action is needed beyond monitoring. If the gap is only a few days, safety stock may absorb it, but that means the buffer is consumed and the next surprise will hit. Use the chart to find the slip at which shortages begin, then agree trigger points with the supplier.
Common mistakes
Using total on hand when part of it is reserved for other orders overstates coverage. Planners also forget in-transit stock or inspection time before receipt becomes usable. In your ERP, check requirement dates in the MRP exception messages or stock requirements list, which show reschedule suggestions for late supply.
Frequently Asked Questions
How do I know the usage rate?
Use the average daily consumption over the next few weeks from the build schedule or requirements list. If usage is lumpy, run the calculator for the period that matters, or per job, rather than relying on an average.
Should safety stock count as coverage?
Count it if you are willing to use it. The tool shows both views: coverage on hand includes it, and a separate output shows how many days it alone would last, so you can see how much buffer is left.
What if the supplier ships in parts?
Run the calculation for the first partial shipment date and quantity, then again for the remainder. A partial that arrives before your coverage ends can eliminate the shortage even when the full order is late.
Does this handle several parts at once?
No, it is one part at a time. For many parts, use a worksheet or a shortage report from the ERP and apply the same logic by item to rank which delays actually hurt.
If you want delayed purchase orders flagged with their shortage exposure automatically inside your ERP, Netray can build that alert.
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