Kit & bundle component reference
This page is a lookup for how a kit or bundle stores its components, what the Workshop shows for each component, which products are allowed to be components, how the Buildable count is derived from component stock, and how the Total unit cost rolls up. It's reference material — for the task of assembling a bundle or kit, see Build bundles & kits in the Workshop. For the difference between the two types, see Kits vs bundles and Product types explained.
How components are stored
A component is a link between a parent (the bundle or kit) and a component product, plus the quantity of that component needed to make one parent.
The relationship runs both ways, and which direction you're reading matters:
| Direction | Answers |
|---|---|
| Parent → components | "What is this bundle or kit made of?" — the Workshop's component list. |
| Component → parents | "What am I part of?" — useful before you archive, delete, or re-price a product that other bundles depend on. |
A single product can be a component of many parents, and a parent can hold many components. Quantity is per one parent and must be at least 1.
When a kit is assembled, its component draw-down is recorded in the inventory ledger. For how those movements post to stock and FIFO layers, see The movement ledger in the Inventory guide.
What the Workshop shows per component
Opening a bundle or kit in the Workshop lists each component with these details:
| Column | Meaning |
|---|---|
| SKU | The component's SKU. |
| Name | The component's name. |
| Quantity | How many of this component go into one parent. |
| Type | The component's product type — Standard, or Kit for a nested kit. |
| Available stock | All-warehouse available stock for the component. Shows 0 when the component has no stock record. |
| Unit cost | The component's unit cost. Shows 0 when no unit cost is set. |
Above the list, the Workshop shows two computed totals: Buildable (how many complete parents you could assemble from current stock) and Total unit cost (the summed component cost of one parent). Both are explained below.
The Available stock shown on a component row is an all-warehouse snapshot for quick reference. It's not a per-warehouse figure, and it isn't the number that gates a real assembly. The Buildable count is computed separately and per warehouse. For authoritative stock numbers and how each state is derived, see Stock states in the Inventory guide.
Which products can be components
Saving the Workshop replaces the parent's whole component set — the list you save is the complete set, not a set of changes, so a component you remove from the list is removed from the parent.
These rules decide whether a save is accepted:
| Rule | Behavior |
|---|---|
| At least one component | A bundle or kit must have at least one component. Saving an empty list is rejected. |
| Allowed component types | A component must be a standard or kit product. Bundle, matrix, blemished, and manufactured products can't be components — the error names the offending SKU. |
| Minimum quantity | Every component's quantity must be at least 1. |
| No self-reference | A product can't be a component of itself. |
| No circular reference | You can't add a kit that already contains this parent, directly or through its own nested components, because it would create an assembly loop. |
A kit's components stay editable regardless of its inventory history — the rules above are the only reasons a save is refused. For that flow and its guardrails, see Build bundles & kits in the Workshop and Convert & auto-detect product types.
Buildable quantity
Buildable answers: given current component stock, how many complete parents could you assemble right now? It's shown for both bundles and kits in the Workshop.
How it's computed
Nested kits are flattened first — a sub-kit is expanded down to its base standard components, with quantities multiplied through each level. Availability is then evaluated per warehouse, and the per-warehouse counts are added together for the total.
Within a single warehouse, each component's buildable count is its available stock divided by the quantity one parent needs, rounded down. The bottleneck — the component with the smallest count — sets the warehouse's Buildable number.
| Behavior | Detail |
|---|---|
| Per-component math | Available stock ÷ quantity needed per parent, rounded down. The bottleneck component caps the count. |
| Nested kits | A sub-kit is flattened to its base components; a kit inside a kit doesn't contribute its own on-hand as if it were a raw part. |
| Quantity multiplication | Quantities compound through the hierarchy. Kit A holds 2× Kit B, Kit B holds 3× Component X → one Kit A needs 6× Component X. |
| Per warehouse, then summed | A parent can only be assembled from stock co-located in one warehouse. Buildable is computed per warehouse and the counts are added. |
| No components | A parent with no components is 0 buildable. |
| Circular references | The flattening walk tracks what it has already visited, so a mis-configured component can't cause an infinite loop. |
The Workshop's Buildable number is a fast display figure. The check that gates a real assembly reads live on-hand at the moment you assemble and locks the stock while it does, so the two can differ briefly if stock has just moved. For how component draw-downs and the finished kit post to stock, see The movement ledger in the Inventory guide.
Total unit cost
Total unit cost is the summed cost of one parent's components: each component's unit cost multiplied by its per-parent quantity, added up and rounded to 2 decimal places.
| Behavior | Detail |
|---|---|
| Formula | Sum of each component's unit cost × its per-parent quantity, rounded to 2 decimal places. |
| Missing costs | A component with no unit cost contributes 0 to the roll-up. |
| Nested kits | A nested kit contributes its own stored unit cost, not a freshly recomputed roll-up of the sub-kit's components. |
| An estimate, not posted COGS | The roll-up uses each component's stored unit cost as-is, which can be stale relative to actual FIFO cost of goods sold. Treat it as an estimate of build cost. |
For how a bundle's revenue is split across its components at sale time (a separate concern from build cost), see Bundle pricing & revenue proration. For actual FIFO cost of goods sold, see FIFO layers & COGS in the Inventory guide.
Before you begin
- Working with components requires access to the Products area and the Bundle Workshop. See Product permissions reference.
- Only bundle and kit products hold components. Standard, matrix, blemished and manufactured products don't appear in the Workshop. See Product types explained.
Next steps
- Build bundles & kits in the Workshop — the task of adding, editing and saving components.
- Kits vs bundles — which type to choose and why.
- Bundle pricing & revenue proration — how a bundle's price splits across components at sale.
- Convert & auto-detect product types — turning a standard product into a bundle or kit.
- Product fields & validation reference — the full field lookup for a product.