What Is a Backorder?

A backorder is an order for an item that is temporarily out of stock - accepted now, fulfilled when new inventory arrives. It is the commercial answer to a stockout: rather than turning the customer away, the seller takes the order, queues it, and ships when replenishment lands. “On backorder” therefore describes both the item’s status and the growing queue of promised-but-unshipped orders behind it.

This guide covers what “backordered” means for a buyer, how a backorder differs from out of stock and from a pre-order, why items land on backorder, how long the wait really is, concrete examples, the backorder rate metric, and how to manage and prevent backorders on both sides of the transaction.

What you will learn

• Backorder vs out of stock
• Backorder vs pre-order
• Why items go on backorder
• How long a backorder takes
• Backorder examples
• Backorder rate: measuring the problem
• Managing backorders well
• How to prevent backorders
• FAQ

Backorder vs out of stock

The two get used interchangeably, but they signal different things. Out of stock is a dead end: no units, no commitment, come back later. Backordered is a live promise: more units are inbound, orders are still being accepted, and each one is (or should be) matched to expected supply with an estimated date. The difference matters in both directions - a seller who marks items “out of stock” loses sales they could have queued, and a seller who accepts backorders without genuine inbound supply is making promises with nothing behind them.

The practical test is whether you can still buy the item. If the checkout button is live and the page shows an expected ship date, it is a backorder. If the button is greyed out and the page says “notify me when available”, it is simply out of stock - the seller has chosen not to take your money until the shelf is refilled.

Backorder vs pre-order

A backorder and a pre-order both take an order against stock you do not yet hold, which is why they blur together - but they sit at opposite ends of a product’s life. A backorder is reactive: the item already exists, has sold before, and sold faster than the last replenishment could cover. A pre-order is proactive: the item has not launched at all, and the buyer is reserving a place in the queue before the first unit ships.

That difference sets expectations. Pre-order customers usually know they are waiting for a launch date and will wait months quite happily. Backorder customers expected the item to be available now, so patience runs thinner - a few weeks of an unexplained backorder is where cancellations start. Treating a restock like a pre-order, with a vague “coming soon” and no firm date, is a common way to lose a sale that a straight backorder with a real ETA would have kept.

Why items go on backorder

• Demand spikes - a product takes off faster than the forecast that sized the last replenishment order.
• Supplier delays - the replenishment was ordered in time but arrives late: production problems, port congestion, raw-material shortages.
• Long lead times - items with a long lead time leave a wide window where a burst of demand cannot be answered until the next shipment, however well planned.
• Reordering too late - stock hit zero before anyone acted, because no reorder point existed or nobody watched it.
• Thin safety stock - the buffer meant to absorb ordinary variation was set too low, so a normal wobble in demand or supply was enough to empty the shelf.
• Bad stock records - the quietest cause: the system showed stock that did not exist (miscounts, unrecorded damage, theft), so orders were accepted against phantom inventory. The fix here is record accuracy, not forecasting.

How long a backorder takes

There is no standard answer - a backorder lasts exactly as long as it takes the next replenishment to arrive and work through the queue. For stock a distributor holds in-region, that can be a few days. For manufactured-to-order, imported, or shortage-hit goods, weeks to months is normal, and many sellers set a 30-day internal limit after which they proactively contact the customer or cancel. Two questions cut through a vague estimate: is the replenishment order actually placed and confirmed, and how many backorders are queued ahead of yours? A date with no confirmed supply behind it is a hope, not an ETA.

Backorder examples

Backorders look different depending on where they sit in the supply chain:

• Retail electronics - a popular games console sells out in the run-up to a holiday. The retailer keeps the listing live with a “ships within 3 weeks” note, because the next container is already booked and on the water.
• Spare parts - a maintenance team orders a pump seal that the distributor does not stock locally. The order is accepted on backorder against the manufacturer’s next production run, with a four-week ETA.
• B2B wholesale - a distributor promises a retailer 500 units but can ship only 300 today; the remaining 200 go on backorder and ship as a second delivery when the factory catches up. This is a partial shipment, and it is often the fairest way to handle a backorder.
• Internal stock - an office runs out of a specific laptop model mid-onboarding. IT places a purchase order with the supplier and the new hire’s machine is, in effect, on backorder until it arrives.

Backorder rate: measuring the problem

If backorders are a recurring theme, the number to watch is the backorder rate: the share of orders you cannot fill from stock at the moment they are placed. The simple version is backordered orders divided by total orders over a period; a stricter version uses backordered line items or units, which better reflects the customer experience when one out-of-stock item holds up a whole basket.

A rising backorder rate is the clearest early warning that demand is outrunning replenishment - useful because it moves before revenue does. But zero is not the goal either: a rate near nothing can mean you are carrying more stock than you need, tying up cash in inventory to buy a service level customers may not notice. Read the trend against your inventory turnover, not as an absolute to be minimised.

Managing backorders well

On the selling side, the habits that keep backorders from souring into cancellations: quote dates from confirmed supplier commitments rather than optimism; tell customers immediately when a date slips; offer alternatives or partial shipment of what is available; and fulfil the queue first-come, first-served so early orders are not quietly jumped. Internally, every backorder is a data point - items that go on backorder repeatedly need a bigger buffer, an earlier reorder trigger, or a second supplier.

On the buying side, the same logic flips: chase confirmed dates, split orders across suppliers for critical items, and keep your own records honest with regular cycle counts so you reorder on real numbers.

How to prevent backorders

Most backorders are preventable, and the levers are well established:

• Set a real reorder point. Trigger replenishment at average daily usage times lead time, plus a buffer - not when the shelf is already empty. This is the single highest-value habit for spare parts and consumables that must always be on hand.
• Hold enough safety stock. Safety stock exists to absorb the normal wobble in demand and lead time; too thin and every wobble becomes a stockout.
• Keep records accurate. Phantom stock is the cause you cannot forecast your way out of - regular counts stop the system from promising units that are not there.
• Diversify suppliers for critical items. A second source turns a single supplier’s delay from a stockout into an inconvenience.
• Plan for peaks. Promotions, launches, and seasonal demand are known in advance; size the replenishment before the spike, not after.

For internal stock like spares and consumables, AMPthilly’s restock module supports per-item reorder points and supplier purchase orders, so you can raise a purchase order when stock hits the reorder point instead of after someone is left waiting.

The takeaway

A backorder is a promise, not a dead end - it keeps the sale alive when stock runs short, but only if the date behind it is real. Manage it with honest ETAs and partial shipments, measure it with the backorder rate, and prevent it with a reorder point, sensible safety stock, and accurate records. The best backorder is the one that never needed to exist.

Related terms

• Stockout - running out entirely; the event a backorder converts into a queued sale
• Lead Time - the supplier delay that defines how long a backorder lasts
• Reorder Point - the trigger that should fire before stock ever reaches zero
• Safety Stock - the buffer that absorbs demand and supply variation before it becomes a backorder
• Cycle Count - rolling counts that stop phantom stock from triggering false promises
• Inventory Turnover - how fast stock moves; fast movers with long lead times are backorder-prone
• BOM (Bill of Materials) - where one backordered component can stall a whole assembly