Inventory how-to

How to prevent overselling

Overselling happens when your stock count in the store is wrong or stale.

Short answer: Overselling happens when your stock count in the store is wrong or stale. Fix it by keeping on-hand numbers accurate, reordering before you hit zero, and reacting fast when a SKU does sell out. There is no single setting that guarantees zero oversells, but good habits remove most of the risk.

Why overselling happens

Overselling usually comes from one of three gaps: stock counts in the store are out of date, you run out faster than expected because demand spiked, or you reorder too late because nobody is watching the numbers day to day. Each of these needs a different fix.

Keep stock counts accurate

If you sell on more than one channel or location, make sure every sale and every stock adjustment gets recorded in your store admin promptly. Any gap between real stock and system stock is where oversells come from. Receiving stock late, including partial deliveries, is a common cause, so update quantities as soon as boxes arrive rather than waiting for a full shipment.

Reorder before you run out, not after

The real fix for overselling is never hitting zero in the first place. That means knowing your reorder point for each SKU: daily sales times lead time plus safety days. If you order only when you notice stock is low, you are already late. A standing reorder point per SKU, checked weekly, catches this before customers can buy something you do not have.

Step by step

  1. List every SKU with a lead time from its supplier and a safety buffer in days.
  2. Calculate each SKU's reorder point: daily sales x (lead time + safety days).
  3. Check on-hand stock against reorder points at least weekly, more often for fast movers.
  4. Record received stock the same day it arrives, including partial shipments.
  5. When a SKU hits zero, mark it out of stock or set inventory to zero immediately so the store stops taking orders for it.
  6. For bundles or multichannel listings, manually reconcile stock across channels since this is not automated by forecasting tools.
  7. Review any SKU that oversold recently and shorten its safety days or supplier lead time if possible.

Worked example

Suppose a candle SKU sells 6 units a day on average, the supplier lead time is 10 days, and you keep 4 days of safety stock. Reorder point = 6 x (10 + 4) = 84 units. If on-hand stock is 90 units and nothing is on order, you still have headroom, but once it drops to 84 you should have a purchase order already placed, not just planned. If you wait until stock hits 20 before ordering, you will run out days before the new stock arrives and risk overselling.

How SteadyShelf helps

SteadyShelf forecasts daily sales per variant and gives you an order-by date per SKU based on lead time and safety days, so you reorder before hitting zero instead of after. It does not do multi-location or multichannel stock sync, so if you sell in more than one place or location, you still need to reconcile stock across those channels manually.

$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.

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FAQ

What if a product sells out despite reordering on time?

Mark it out of stock or set its quantity to zero in your store admin as soon as you know, even before you update other records. The faster you stop sales on a zero-stock item, the fewer oversold orders you have to apologize for and refund.

Does safety stock fully eliminate overselling risk?

No. Safety days cover normal demand swings and minor supplier delays, but a big spike in sales or a late shipment can still push you to zero. Review any SKU that oversells and increase its safety days or tighten supplier lead times going forward.

Let SteadyShelf do this math for every SKU

Order-by dates per supplier, seasonal forecasts and draft POs for your Shopify store. $29/month after a 30-day free trial.

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