How a reorder proposal is calculated
Role: adminRole: managerUpdated 2026-08-29
What is calculated
One number per article and warehouse: how much to order so the shelf carries through until the next delivery arrives.
Inputs
| Input | What it is |
|---|---|
| Available | On the shelf and not promised away. |
| On order | Ordered and not yet delivered. |
| Per day | Quantity sold per day, averaged over the consumption window. |
| Cover days | The supplier's lead time plus the buffer. |
| Minimum | A floor set by hand on the article. Optional. |
| Pack size | The supplier's carton. |
| Minimum order quantity | The least the supplier will sell. |
The rule
- Target = the larger of per day × cover days and the hand-set minimum. Each knows
something the other does not: the minimum knows the article that must be there although it sells twice a year, consumption knows the article nobody ever set a minimum for.
- Shortfall = target − (available + on order). Quantity already on its way counts, or
the same gap would be proposed every day until the pallet arrives and somebody orders it twice.
- Proposal = the shortfall rounded up to whole cartons. If that is below the minimum
order quantity, the minimum is used — and rounded up to cartons again.
- A shortfall of zero or less proposes nothing, and the article is not listed.
Worked example
Available 4, on order 6, sold 90 over a 30-day window, lead time 7 days, buffer 3 days, no minimum, carton of 6, minimum order quantity 10:
| Step | Result |
|---|---|
| Per day | 90 ÷ 30 = 3 |
| Target | 3 × 10 = 30 |
| Shortfall | 30 − (4 + 6) = 20 |
| Rounded to cartons | 24 (4 cartons of 6) |
| Above the minimum order quantity | yes, stays 24 |
A minimum order quantity of 10 with a carton of 6 means 12, not 10 — otherwise the order is one the supplier cannot pick.
What this does not change
- Nothing is ordered. The proposal creates drafts, and a draft is not an order.
- A window of zero days measures nothing and yields no opinion, rather than an error.