Reorder point calculator
Find out at which stock level to reorder a product, how much safety stock to hold and by when the next order has to go out. Free, no signup, works for any store.
30 to 90 days is a good window. Average daily sales: 2.0
Extra days of sales kept in stock for late deliveries or a busy week.
How much daily sales swing. Not sure? Use about half of your average daily sales.
Place the next order when stock falls to this level.
- Average daily sales
- 2.0
- Demand during lead time
- 28
- Safety stock
- 14
- Suggested order quantity
- 60
- Stock lasts
- –
- Order by
- –
Doing this for 200 SKUs?
ReorderSheet runs this calculation for every product in your Shopify store at once, from the order and inventory CSV exports you already have. You get a list of what to reorder, how many units and when each SKU runs out, plus the cash tied up in dead stock. $29 once, runs in your browser, files are never uploaded.
The reorder point formula
The first part covers what you sell while you wait for the delivery. Safety stock covers the days when sales run higher than usual or the supplier is late. Once stock on hand drops to the reorder point, the next order goes out, and in theory the delivery arrives just as the safety stock starts to be used.
Two ways to set safety stock
Buffer days is the practical method: decide how many extra days of sales you want on the shelf.
Service level is the statistical method. It sizes the buffer by how much your daily sales swing and how often you are willing to sell out.
Z is 1.28 for a 90% service level, 1.65 for 95%, 1.96 for 97.5% and 2.33 for 99%. Going from 95% to 99% raises safety stock by about 40%, so reserve high service levels for bestsellers.
Worked example
A product sold 60 units in the last 30 days, so 2 units a day. The supplier needs 14 days. You want 7 buffer days.
- Demand during lead time: 2 × 14 = 28 units
- Safety stock: 2 × 7 = 14 units
- Reorder point: 28 + 14 = 42 units
With 40 units on hand you are already below the reorder point and should order today. With 70 units on hand stock lasts 35 days, and the order has to go out within 14 days (when 42 units are left).
How much to order
The reorder point tells you when to order. For how much, a simple rule is to cover the days until your next regular order: average daily sales × days to cover, plus whatever you are short of the reorder point. Minimum order quantities and case packs from your supplier come on top.
Getting the numbers from Shopify
- Units sold: Analytics → Reports → sales by product variant, for the last 30 to 90 days. Use a window without a one-off sale or stock-outs, otherwise the average is off.
- Lead time: from the day you send the purchase order to the day the goods are sellable, including shipping and receiving.
- Stock on hand: Products → Inventory, or the inventory CSV export.
Common mistakes
- Using sales from a period when the product was sold out. Days with zero stock pull the average down, so the reorder point ends up too low.
- Counting only shipping time as lead time and forgetting production and receiving.
- One safety stock rule for every product. Slow sellers with high safety stock tie up cash for months.