When should you reorder a Shopify SKU?
Compare how long your stock may last with how long replenishment takes. A reorder point gives you a clear threshold you can check.
A worked example: 10 days of stock, 14 days to replenish
Synthetic example using Stocklight's sample data. This is not a customer result.
The example SKU sold 60 units during 30 days in stock. Its daily sales rate is 60 ÷ 30 = 2 units a day. With 20 available units, estimated coverage is 20 ÷ 2 = 10 days.
Waiting until stock reaches zero would leave too little time for this supplier. With a 7-day safety buffer, the reorder point is 2 × (14 + 7) = 42 units. Current stock is below that threshold, so Stocklight flags a reorder.
The formulas Stocklight uses
- Daily sales rate = recent units sold ÷ recent days in stock.
- Days of stock = available units ÷ daily sales rate.
- Reorder point = daily rate × (supplier lead time + safety days), rounded up to a whole unit. Reorder when available units are at or below this point.
- Suggested order, when a reorder is triggered = daily rate × (lead time + safety days + order coverage days) − available units, rounded up and never below zero.
For the example, a 30-day order coverage period gives 2 × (14 + 7 + 30) − 20 = 82 units. This is a formula suggestion, not a purchase order. Incoming orders are not deducted; check them, minimum order quantities, pack sizes and promotions before ordering.
What data do you need from Shopify?
A Shopify inventory export provides current quantities. Choose one stock location and use available units, rather than stock already committed to customers or unavailable to sell. Shopify describes the export formats in its inventory CSV guide.
A current inventory snapshot alone cannot supply all the history needed for this calculation. You also need:
- Sales totals for the recent period and up to 90 days of available history.
- The actual days each SKU was in stock during those periods.
- Supplier lead times, plus your chosen safety buffer and order coverage period.
Use the same stock location and date windows for sales and stock. Do not guess missing in-stock days or mix store-wide sales with one location's stock. Stocklight requires at least 7 recent days in stock for a sales-rate estimate. Zero recent demand has unknown coverage; missing evidence can produce an insufficient-data result.
Prepare a Shopify inventory export, then fill verified history into the worksheet. The CSV guide lists the exact required columns and limits.
When should you adjust the result?
Review seasonal changes, promotions, supplier delays and recent stockouts. Historical sales can understate demand when an item was unavailable; this method does not estimate lost sales or future demand changes. Check the numbers yourself before committing to an order.
Get a clear action list for your store
Run a free scan in your browser, with no account or Shopify connection. If you want help checking your data and prioritizing the results, Stocklight offers a one-time THB 990 inventory review for up to 50 SKUs in one location. Request a data-readiness check first; pay only after scope, delivery and cancellation/refund terms are confirmed by email.