Safety Stock, Reorder Point & EOQ Calculator
Compute safety stock, reorder point and economic order quantity for an inventory item from demand variability and lead time.
How to Use the Safety Stock, Reorder Point & EOQ Calculator
- Pick target service level.
- Enter σ of daily demand and lead time.
- Enter average daily demand.
- Enter annual demand, order cost, and unit holding cost.
- Click Calculate to see safety stock, ROP and EOQ.
使用场景
- •Retail inventory planning.
- •Manufacturing raw-material buffers.
- •Teaching operations management.
公式
Safety stock = Z × σ_demand × √lead time. ROP = average demand × lead time + safety stock. EOQ = √(2 × annual demand × order cost / holding cost).
常见问题
What service level should I choose?
Higher service levels reduce stockouts but balloon inventory. 95% is the common default; 98–99% only for critical SKUs.
Does this assume normal demand?
Yes. For highly skewed demand (long-tail retail), use a Poisson or empirical model instead.
How do I get σ_demand?
Compute the standard deviation of daily sales over a stable period (90–180 days is typical).