Free tool
Reorder point calculator
Find the stock level that should trigger your next purchase order, how many days of stock you have left, and roughly when to order. Everything updates as you type, and the link keeps your numbers.
The reorder point formula
Reorder point = average daily sales × lead time + safety stock
Lead-time demand is what you expect to sell while waiting for a delivery. Safety stock is the buffer for days when sales run hotter or the supplier runs late. When stock on hand plus units already on order falls to the reorder point, it's time to order.
Example
You sell 12 units a day and your supplier takes 21 days. Lead-time demand is 12 × 21 = 252 units. If your busiest day is 18 units and the slowest delivery took 28 days, safety stock is 18 × 28 − 12 × 21 = 252 units, so the reorder point is 504.
That simple safety stock method is easy but often generous. The service-level method uses how much daily sales actually vary; see the safety stock guide for when to use each, or compare all three methods with the safety stock calculator.
What a calculator can't do
- Exclude days a product was out of stock, which otherwise make demand look lower than it is.
- Notice when a product's sales trend changes or a supplier starts delivering late.
- Repeat this for every SKU, every day.
That is what Reorder Radar does automatically from your Shopify data.
Want this for every product?
Reorder Radar runs this for every SKU from your Shopify data, excluding stockout days and tracking real supplier lead times. The Shopify App Store listing is in review: leave your email for the install link, or look around the live demo first.