Assign lots to orders, adjustments, stocktakes and builds

Once lots are recorded at receiving (see Lot tracking: batch numbers and expiry dates), this is where they get used. Lots are a record beside your inventory: assigning or consuming one never changes your Shopify stock levels.

On a Shopify order, the Stockroom - Lots block lists the order's lot-tracked items with a suggestion for which lot the units should come from - the batch expiring soonest comes first, split across batches when one can't cover the quantity. Review it, change any line, and Save: the units come out of those lots, and each lot's page lists the order in its history. You'll find the block on the order page in the apps area - pin it to keep it in view.

By default an assignment is yours to confirm - the block suggests, and nothing moves until you Save. If you would rather not confirm every order, turn on Assign lots automatically when an order is fulfilled under Settings > Purchase orders > Early access, just under the lot tracking box. From then on, the moment Shopify marks an order fulfilled (or part of it), each lot-tracked line that still has units unassigned takes the batch your picker scanned on the pick list if there was one, otherwise the batch expiring soonest (oldest first), and that lot's balance goes down. It only ever fills what is still unassigned: a lot you assigned by hand is never changed, a recalled batch is never chosen, and if your lots do not hold enough units it assigns what exists and leaves the rest for you to settle in the block. It applies to orders fulfilled from the pack bench, from a POS pickup, and straight from the Shopify admin alike.

📸 SCREENSHOT: Settings > Purchase orders > Early access with lot tracking on and the "Assign lots automatically when an order is fulfilled" box beneath it

Clearing an assignment puts the units back in the lot, and a refund doesn't return units automatically - adjust the lot if you restock them.

If you pick with pick lists, each lot-tracked line shows which lot to take (the assignment on the order, or the same soonest-expiry suggestion), and scanning the batch label at pick confirms it. The packing slip can print the lot under each item for the customer's records - see Pack and finish orders at the bench.

When you write off or find stock, you can say which batch it belongs to. On a stock adjustment, lines for lot-tracked products get a Lot column: pick the lot the units are leaving (a negative adjustment) or joining (a positive one). The pick is optional - a correction with no lot still updates Shopify, it just leaves your lot balances alone. The column appears as soon as a tracked product is on the adjustment, whether you typed, scanned or browsed it in.

Putting existing stock into a batch. The same column is how you record a batch number for stock already on your shelves, which is what you need when you start tracking lots on a product you have been selling for a while. Choose New lot in the Lot column and type the batch number. If the stock count is right and only the batch number is missing, leave the change at 0 and type how many units belong to the batch in Units to assign - the adjustment then changes nothing in Shopify, it only records the lot. Applying the adjustment creates the lot and puts those units in it. If the same number arrives on a purchase order later, it joins the batch you made rather than starting a second one. You can add an expiry date afterwards on the lot's own page.

Stocktakes work the same way at the review step. You count the shelf as usual - one count per product, since every batch shares the same barcode - and any line with a difference shows a Lot select where you can say which batch the missing or extra units came from. When you apply the stocktake, that lot moves along with the Shopify correction.

Lot balances move when the document is applied, not when it is saved, and Stockroom refuses to apply one that would take more units out of a lot than it holds - adjust the lot first if its balance is wrong. Each lot's page lists these movements as Adjustment or Stocktake with the document number, linked to it.

When you record a build, you can track both sides of it. If a component is lot-tracked, its line in the Record build dialog gets a Lot select - pick the batch those parts came from, and the lot's balance goes down by what the run consumed. Picks are optional, and Stockroom refuses to record a run that would take more units out of a lot than it holds.

If the product you're making is lot-tracked, the same dialog offers a Lot number field - prefilled with the build number, like BLD-1024 - and an optional Expiry. The units you record join that batch, so a production run becomes a traceable lot of its own. Type a different number to add to an existing batch, or clear the field to skip it. Scrapped units never enter a lot.

Undoing a run puts everything back - the component lots and the output batch. Each lot's page lists these movements as Build with the build number, linked to it. Components issued to a build ahead of time aren't drawn from a lot until a run consumes them.

Unbuilds work the same way in reverse. In the Record unbuild dialog, a lot-tracked product gets a Lot select for the batch the units you're taking apart come out of, and each lot-tracked component gets a Lot number and optional Expiry for the batch the recovered parts go back into - type an existing number to rejoin it, or a new one to start a batch. Leave either blank to skip it.