What to do when your best seller runs out

Find out why it happened first

Before you order anything, check when the item hit zero and compare that to when it should have been reordered. If you reorder manually, look at your last order date, the supplier's lead time, and your sales since then. Usually the order either went out too late or the quantity was too small for how fast the variant was selling.

Knowing the cause matters because it changes the fix. A late order means you need a trigger date, not just a bigger order. A too-small order means your reorder point or safety stock was wrong for current sales speed.

Place the right emergency order

Do not just guess a round number. Work out your current daily sales rate from the last few weeks, not from months ago, because a best seller's pace can shift. Then size the order to cover the supplier's lead time plus enough buffer days so you are not back at zero the moment stock lands.

If the supplier can do a partial or rush shipment, ask for it, even at a higher cost per unit. Being out of your best seller for an extra two weeks usually costs more in lost sales than a rush fee.

Decide what to do about lost sales

You cannot recover the sales you already lost, but you can manage the gap. Put the product page up with an expected restock date if you know one, instead of hiding the listing. Customers who want a specific item will often wait a short time if they know when it is coming back.

Avoid discounting other items to "make up" for the stockout. That does not bring back the lost sales, it just lowers margin on top of the lost revenue.

Fix the system so it does not repeat

Go back to your reorder point for that variant: daily sales times (lead time plus safety days). If the stockout happened before that point was reached, your sales forecast was outdated. If it happened because the order sat unplaced past the trigger date, you need a clearer order-by date and a habit of checking it weekly, not monthly.

For a genuine best seller, consider raising the safety days specifically for that SKU, since the cost of running out is higher than for a slow mover. A few extra days of stock on your top item is cheap insurance.

Step by step

1. Check your sales history to find the exact day stock hit zero
2. Calculate current daily sales rate using the last 2-4 weeks only
3. Call the supplier to ask about rush or partial shipment options
4. Size the emergency order: daily sales x (lead time + buffer days), minus anything already on order
5. Update the product page with a restock date if you have one
6. Recalculate the reorder point for this SKU using the new daily sales rate
7. Add extra safety days to this specific variant going forward

Worked example

Say your best seller was selling 10 units a day, and your supplier's lead time is 14 days. Your reorder point should have been 10 x (14 + 3 safety days) = 170 units remaining. If you placed the reorder when only 40 units were left, you were already 130 units of lead time behind, which is why it ran out before the new stock arrived. For the emergency order, with 0 on hand and nothing yet on order, you'd order 10 x (14 + 7 days of cover) = 210 units to cover the gap and rebuild a buffer.

How SteadyShelf helps

SteadyShelf is built for exactly this: it tracks the 28-day sales rate per variant and gives you an order-by date per SKU, so a best seller gets flagged before it hits zero rather than after. It will not place a rush order with your supplier for you or manage the "out of stock" messaging on your product page, those parts are still on you.

$29/month flat, unlimited products and suppliers, 30-day free trial. Run the numbers now with the free reorder point calculator.

SteadyShelf is launching on the Shopify App Store. Join early access to get the install link first.

Related guides

• What to do when your forecast is wrong
• What to do with excess inventory after the holidays
• What to include on a purchase order
• What to do when sales suddenly spike

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