Reorder point calculator
The stock level that should trigger a reorder — computed from how fast you use an item and how long the vendor takes.
When stock hits 72, reorder — you'll consume ~56 units during the 7-day wait, landing on your 16-unit safety cushion.
The formula
Reorder point = (average daily usage × lead time in days) + safety stock
Logic, in one breath: from the moment you reorder, you keep consuming stock until the delivery lands. The formula makes sure you start that clock while you still have enough to cover the wait — plus a cushion for the weeks that don't behave like averages.
Getting honest inputs
Daily usage comes from consumption history — last quarter's usage ÷ 90 beats anyone's gut feel. Lead time is order-to-shelf, not the courier's transit estimate: include vendor processing and your own receiving.Safety stock absorbs variability in both — size it with the safety stock calculator rather than guessing.
A worked example
A fab shop burns ~8 sticks of MIG wire a day; the supplier takes 7 days door-to-shelf; safety stock is 16 (two days' cover). Reorder point = 8 × 7 + 16 = 72. The wire rack dips to 72, a PO goes out, ~56 sticks get consumed during the wait, and the delivery lands with the cushion intact.
The part no formula fixes
A reorder point only works if something is watching it. A number in a spreadsheet column relies on a human noticing the moment stock crosses it — which is precisely the kind of vigilance floors are bad at. In inventory software, the reorder point watches itself: stock dips, a purchase order drafts with the vendor's lead time attached, and the shelf refills without anyone playing sentry.