Inventory EOQ & Reorder Calculator
Calculate EOQ, reorder point, annual orders, and order cycle
Inventory EOQ & Reorder Calculator — what it does
Calculate the economic order quantity from annual demand, cost per order and annual holding cost per unit, and the reorder point from daily demand, lead time and safety stock. Together they answer the two questions inventory management runs on: how much to order, and when to place the order.
When this tool helps
- Setting order quantities that balance bulk-buying savings against the cost of holding stock.
- Establishing reorder triggers so a supplier's lead time never turns into a stockout.
- Reviewing whether current ordering habits are actually economical or just habitual.
How to use it
- Enter annual demand, cost per order and annual holding cost per unit.
- Enter average daily demand, lead time in days and safety stock.
- Calculate the results.
- Read EOQ, reorder point, orders per year and the order cycle.
Accuracy, limits, and good practice
- Holding cost is more than warehouse space: capital tied up, insurance, obsolescence and shrinkage all belong in the figure.
- EOQ assumes steady demand and a fixed lead time. Seasonal or volatile products need the result treated as a starting point, not an answer.
- Safety stock is what absorbs variability — set it from how badly your lead times and demand actually swing, not from optimism.
Frequently asked questions
What does the EOQ formula balance?
Ordering cost against holding cost. Frequent small orders raise ordering costs; large rare orders raise holding costs, and EOQ is the minimum of the total.
How do I set safety stock?
Cover the gap between average and worst-case demand across the lead time. Higher service levels need proportionally more.
Does this handle supplier minimums or discounts?
No. Compare the EOQ against minimum order quantities and price breaks yourself; a discount can justify ordering above EOQ.
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Everything above runs inside this page. Inventory EOQ & Reorder Calculator needs no account, no upload, and no server round trip — close the tab and nothing is left behind.
庫存 EOQ 與補貨點計算器能做什麼
由年需求量、每次訂購成本與每單位年持有成本計算經濟訂購量，再由日均需求、前置期與安全庫存計算補貨點。兩者合起來回答了庫存管理賴以運作的兩個問題：一次訂多少，以及什麼時候下單。
什麼時候用得上
- 設定訂購量，在大量進貨折扣與庫存持有成本之間取得平衡。
- 建立補貨觸發點，讓供應商的前置期不會演變成缺貨。
- 檢視目前的訂貨習慣究竟是划算，還是只是習慣。
使用步驟
- 輸入年需求量、每次訂購成本與每單位年持有成本。
- 輸入日均需求、前置期天數與安全庫存。
- 執行計算。
- 查看 EOQ、補貨點、年訂購次數與訂購週期。
精確度、限制與實務建議
- 持有成本不只是倉租：積壓資金、保險、過時損失與損耗都該算進去。
- EOQ 假設需求穩定、前置期固定。季節性或波動大的商品，請把結果當成起點而非答案。
- 安全庫存是用來吸收變異的——請依前置期與需求實際的波動幅度設定，而不是憑樂觀。
常見問題
EOQ 公式在平衡什麼？
訂購成本與持有成本。頻繁小量下單會推高訂購成本，大量少次會推高持有成本，EOQ 就是總成本的最低點。
安全庫存怎麼設？
要能涵蓋前置期內平均需求與最壞情況之間的差距。服務水準要求越高，需要的量就越多。
有考慮供應商最低訂量或折扣嗎？
沒有。請自行把 EOQ 與最低訂量、價格級距比對；折扣有時足以支撐訂超過 EOQ 的量。
本站相關工具
以上步驟全部在這個頁面內完成，庫存 EOQ 與補貨點計算器 不需要註冊、不上傳檔案、也不經過伺服器，關閉分頁後不會留下任何資料。