What this tool checks
Daily demand is a weighted average of up to the most recent four weeks, where recent weeks receive greater weight. Reorder point = ceiling(daily demand × (lead time + safety days)). Target quantity = ceiling(daily demand × (lead time + safety days + desired coverage)) minus current stock.
Worked example
Four weeks selling 70 units each yield 10 units/day. With 10 supplier days and 4 safety days, the reorder point is 140 units. At 100 available, reorder is advised.
Assumptions and limitations
Simple planning model. Assumes sales occurred over comparable complete weeks, constant supply timing and no seasonality; future demand and supplier delays are uncertain.