Reorder before you run out

A stockout loses the sales you could have made and, often, the ad spend that was still sending buyers to a sold-out product. Ordering too early ties up cash in stock that sits on a shelf. The reorder point is the stock level at which a new order must be placed so that it arrives just as the current stock runs out, with a cushion of safety stock for the days when sales run faster than usual or the supplier runs late.

How it is calculated

  • Demand during lead time = average units sold per day x supplier lead time in days.
  • Safety stock = average units sold per day x safety days.
  • Reorder point = demand during lead time + safety stock.
  • Stock position = units in stock + units already on order.
  • Days of stock left = units in stock / average units sold per day.
  • Suggested order quantity = daily sales x (lead time + days of cover) + safety stock - units in stock - units on order.

If the stock position is at or below the reorder point, it is time to order. A product selling 12 units a day with a 20-day lead time and 7 days of safety stock has a reorder point of 324 units. With 300 in stock and nothing on order, it should be reordered now; to cover 30 days after the delivery arrives, the order is 12 x 50 + 84 - 300 = 384 units.

How to fill it in

It doubles as a safety stock calculator: the safety days you enter become the safety stock in units.

  • Average units sold per day: units sold over the last 30 to 90 days, divided by the days. Use a recent period if sales are growing.
  • Supplier lead time: days from placing an order to having the stock ready to sell, including shipping and receiving.
  • Safety days: how many extra days of sales to keep as a cushion. More for unreliable suppliers or volatile sales.
  • Units in stock and on order: what you have and what is already on its way.
  • Days of stock to order for: how long the new order should last after it arrives. 30 days if left blank.

Limitations

The calculator assumes steady daily sales. It does not see seasonality, promotions, minimum order quantities, case packs, supplier price breaks or cash constraints, so round the quantity to what your supplier sells and adjust for any sale you are planning. It covers one product at a time. Everything runs in your browser and nothing is sent or stored.

Across the whole catalog

ORVX reads your stock and sales from Shopify and shows stock cover, the cash held in inventory and what to reorder across every product, so a reorder decision starts from your real sales rather than a typed average.

Worked examples

Illustrative figures, not benchmarks.

A steady seller

12 units a day, 20 days of lead time and 7 days of safety stock give a reorder point of 324. With 300 in stock, reorder now: 384 units cover the next 30 days.

Long sea freight

5 units a day with a 45-day lead time and 14 safety days give a reorder point of 295. 400 units are above it, so not yet: you have 80 days of stock.

Fast mover with stock on the way

30 units a day and only 5 days of stock, but 200 units are on order. Stock position is above the reorder point of 300, so no new order is needed.

Common mistakes

  • Using a sales average that includes days the product was out of stock.
  • Ignoring production time and counting only shipping.
  • Forgetting stock already on order.
  • Using one safety stock for every product.

Questions

How much safety stock do I need?

Enough days to cover the delays and sales spikes you have actually seen. Start from your worst recent lead time.

Does it work per variant?

Yes, and it should be used per variant: sizes rarely sell evenly.