Purchasing & suppliers
Back-to-Back Order (Special Order)
By the Supply Chain Manager team · Updated October 16, 2026
A back-to-back order is a purchase order raised only when a specific customer order arrives, so the item is bought for that customer rather than for stock.
The goods may come into your warehouse and go straight out, or be drop shipped. Either way, there is no stock risk: you buy only what is already sold.
The trade-off is lead time. A customer who could have had the item today from stock now waits for the supplier's lead time plus your handling. That is usually acceptable for unusual items, and it is honest to tell customers which lines are stocked and which are ordered in, so they can plan.
Back-to-back order example
Illustrative: a contractor orders 40 units of a light fitting you do not stock. You raise a PO for exactly 40 with a 5-day lead time and promise delivery in 7 days.
Why back-to-back order matters for distributors
Moving rarely sold SKUs to back-to-back ordering is one of the cleanest ways to cut slow-moving stock while still serving the customers who need them.
Common back-to-back order mistakes
- Stocking items that sell only through occasional special orders.
- Losing the link between the customer order and the PO, so the goods are not reserved on arrival.
Examples on this page use made-up round numbers to show the calculation. They are not benchmarks or results from real businesses.