Assembly SKUs: What They Are and How to Set One Up
Last updated: July 29, 2026
An Assembly SKU is a finished product that gets built in the warehouse out of two or more component SKUs. Once it is built, it becomes its own trackable inventory item with its own bin location and on hand count, and it ships as a single unit.
Assembly SKUs are the foundation for Work Orders. If you want us to pre-build bundles, gift sets, or multipacks so they are ready to pick and ship as one item, the Assembly SKU has to exist and be configured first.
Assembly SKU vs. Kit
These two get confused often, and choosing the wrong one causes inventory problems later. The short version is that a Kit is a selling construct and an Assembly SKU is a manufacturing construct.
Kit | Assembly SKU | |
|---|---|---|
What it is | A virtual bundle. The order breaks apart into components at pick time. | A real, physical item built ahead of time from components. |
Can hold on hand inventory | No | Yes |
Can be assigned a bin location | No | Yes |
Built in advance | No, assembled at the pick station on every order | Yes, built in batches through a Work Order |
Best for | Bundles you sell occasionally, or bundles whose contents change often | High volume bundles, retail ready sets, anything that needs to be sealed or packaged as one unit |
If you are not sure which one fits, send us the SKU and a description of the bundle and we will make the call with you.
Requirements
An Assembly SKU has to have at least one component. In practice it should have two or more, otherwise there is nothing to assemble.
The Assembly SKU and all of its component SKUs need to already exist in the catalog before the assembly relationship can be built.
How to set up an Assembly SKU
Open the product details page for the SKU that will become the finished item, then select the edit icon.
Enable the setting This is an Assembly SKU used in Work Orders and click Update.
An Assembly SKU components section appears on the product page. Search for each component SKU and select it from the drop down to add it.
To set how many units of a component go into one finished unit, click Quick Edit on that component line, update the Assembly Component Quantity, and click Update.
Repeat step 3 and step 4 for every component in the build.
Editing components later
You can change the components of an Assembly SKU at any time. The change applies to new Work Orders only. Any Work Order that already exists keeps the components it was created with.
This is intentional and it is useful. Say a gift set is defined as one hat, one shirt, and one blue sticker, and you run out of blue stickers partway through. You can swap the sticker component to a different SKU and create a second Work Order against the new definition. The first Work Order still consumes blue stickers, and the new one consumes the replacement.
The tradeoff is that the SKU definition is not a historical record. If the contents of a bundle change permanently and you need clean reporting, it is usually better to create a new Assembly SKU than to edit the existing one.
What happens next
Once the Assembly SKU is configured, the build is requested through a Work Order. The Work Order tells the warehouse how many finished units to build, pulls the component inventory from its locations into a staging area, and then converts that component inventory into on hand inventory for the finished Assembly SKU once the build is complete. Every one of those inventory movements is logged.
If an Assembly SKU goes into backorder, a Work Order can be generated automatically for the backordered quantity, so builds keep pace with demand instead of waiting on someone to notice.
Common questions
Will the components still show as available while a Work Order is open? Component availability is calculated as on hand minus allocated. When a Work Order is created, the components it needs are accounted for, so plan around the available number rather than the on hand number.
Can I convert an existing product with inventory into an Assembly SKU? Talk to us first. A SKU that already has bin locations and on hand quantity needs to be handled carefully so the counts stay clean. In most cases a new SKU for the finished item is the safer path.
Do I need lot tracking on the Assembly SKU? Only if the finished item itself needs a lot code or expiration date. Lot tracking on a component does not carry up to the finished item automatically. If you need it, enable Needs Lot Tracking on the Assembly SKU before any Work Orders are created, because assigning lots after the fact has to be done manually.
How long does a build take? It depends on the number of units, the number of components, and how much packaging work is involved. Send us the SKU and the target quantity and we will confirm a turnaround time before we start.