The stock-out you saw coming too late
Your supplier needs time to produce. Then the goods sit waiting for a vessel, cross the sea, clear customs, go to your warehouse or prep centre, get labelled, and finally travel to an Amazon fulfilment centre where receiving takes its own time. When you add it up, the order you place today covers sales well into the future. And the day you realise you should have ordered is the day it is already too late.
Most sellers manage this with a spreadsheet: current stock, average sales, a lead time column and a reorder date. It works until a vessel is delayed, a peak season doubles sales or the prep centre falls behind, and then the spreadsheet quietly stops being true.
Why one lead time number is not enough
Lead time is not a single figure. It is a chain of stages, each of which varies with the season and the supplier, and each of which holds stock that you cannot sell yet. A spreadsheet with one lead time column hides where your stock actually is.
| Stage | What varies |
|---|---|
| Production | Factory capacity, holidays, raw materials |
| Waiting for shipment | Vessel space, consolidation with other orders |
| Ocean or air freight | Route, weather, port congestion |
| Customs and delivery | Paperwork, inspections, haulage |
| Prep and send to FBA | Prep centre workload, labelling |
| FBA receiving | Fulfilment centre workload, capacity limits |
Around peak trading periods, several of these stretch at once, which is exactly when running out hurts most.
What bad timing costs
Stock-outs on Amazon are expensive beyond the lost sales. The listing loses momentum, ranking slips and it takes spending on ads to recover once stock is back. Overbuying is expensive differently: cash tied up in stock, storage fees, aged inventory surcharges and, eventually, discounting.
Many sellers respond by paying for air freight in a panic, which fixes this order and eats the margin on it.
Take a seller of garden furniture covers. Spring demand arrives in a rush. The reorder was placed on the usual date, but the factory closed for a holiday, the vessel was rolled to the next sailing and the prep centre was busy with everyone else's spring stock. Each delay was small. Together they meant the covers arrived at the fulfilment centre after the first warm weekend, when most of the season's buyers had already bought from someone else. Nothing in the spreadsheet warned anyone, because the spreadsheet had one lead time and it had not changed.
The reorder plan we build
- A purchase order record for each order with your supplier, with the stages above and the expected date for each, updated as your supplier or forwarder confirms them.
- Current FBA inventory and inbound quantities read through the Selling Partner API, plus stock at your warehouse or prep centre.
- A sales forecast per SKU based on recent sales with a seasonal adjustment you control, and planned events such as deals marked in advance.
- A day-by-day stock projection for each SKU, showing when each purchase order becomes sellable stock and where the projection falls below the safety level you set.
- A reorder date per SKU: the last day an order can be placed with normal freight to avoid a gap, and a warning when that date is close.
- Alerts when a stage slips, such as a delayed vessel, showing which SKUs are now at risk of running out and by how much.
Freight updates can come from your forwarder's emails, a shared sheet or their portal if it has an export. We use whatever you already receive.
What planning looks like afterwards
Once a week, the buyer opens a list of SKUs that need ordering soon, with the reason and the projected gap. Open purchase orders show where each one is and whether it is on time. When a vessel slips, the plan shows the knock-on effect straight away, so you can decide whether to send some stock by air or accept a short gap on a less important SKU.
Because every stage has a date, you also build up real lead time history per supplier and route. After a few orders, you know which supplier is consistently late and which forwarder's estimates can be trusted.
Does your reordering look like this?
- Your reorder spreadsheet has a single lead time column.
- You have run out of stock on a bestseller while an order was at sea.
- Air freight is used regularly to cover late orders.
- Nobody knows exactly which stage each purchase order is at.
- You overbought before peak because nobody trusted the numbers.