Definition
Order-by date is when you must place a purchase order so that, given lead time, stock arrives before the projected stockout. It is the date form of a reorder point.
Formula
Order-by date ≈ stockout date − lead time in days
(With safety stock baked into the stockout projection)
(With safety stock baked into the stockout projection)
Worked example
Stockout projected 12 June, lead time 35 days → order by about 8 May. Miss that date and you burn safety stock or go dark.
Why it matters for replenishment
Buyers work from calendars and supplier cut-offs. A date is easier to act on than a unit threshold alone.
How OmniRestock uses this
OmniRestock produces order-by dates per SKU from forecast, lead time and safety stock, and can surface them in alerts and calendars.