A starter kit, a gift box, a service pack, a machine sold with its spares: a kit is a product you sell as one item and hold as several. The components sit on the shelf. The kit exists when someone puts them in a box.
That gap between how you sell it and how you hold it is where kits go wrong. The price list says you have the kit. The shelf says you have most of its parts.
How many can you build
For each component, divide what you have available by what one kit needs, and round down. The kit’s availability is the smallest of those numbers.
| Component | Per kit | Available | Kits possible |
|---|---|---|---|
| Base unit | 1 | 42 | 42 |
| Power adapter | 1 | 65 | 65 |
| Cable | 2 | 70 | 35 |
| Printed guide | 1 | 400 | 400 |
| Box | 1 | 38 | 38 |
You can build 35 kits, and the cable is the limit. The base unit, the expensive part everyone watches, is not the constraint. The €0.80 cable is, and so is the box, with 38.
Two refinements make the figure honest:
- Available means available. Components already reserved for another job, or held on a supplier claim, are not available for this one. Count only free stock.
- Shared components count once. If the cable also goes into another kit you plan to build this week, the two kits compete for the same 70 cables. Plan them together or the second one stops halfway.
When the components should leave stock
There are two moments to choose from, and the choice matters more than it looks.
At assembly. Components leave stock when the kit is built, and the kit comes into stock as a product of its own, with its own quantity. Use this when kits are built in advance and sit on the shelf, or when a built kit cannot easily be taken apart again.
At sale. Components stay as components until the kit is sold, and leave stock at that moment. Use this when kits are built to order from parts that also sell on their own, so that a cable is available to any order until the moment one claims it.
What does not work is a mixture nobody has written down: some kits built ahead and recorded, some built on the fly and not recorded, and a component count that is right on alternate Tuesdays.
Costing the kit
A kit is worth its components, under whatever valuation method you use, plus whatever it costs to put it together: the box, the label, ten minutes of someone’s time. Kits priced from the main component’s cost alone look more profitable than they are, because the cables, boxes and labour are each small enough to ignore and together are not.
Keeping the kit from hiding a shortage
The usual failure is a kit whose main component is plentiful while a minor one runs out, unnoticed, because nobody set a reorder point for a box.
- Every component gets a reorder point, including packaging and printed material. The cheaper the part, the more likely it is to be the one that stops the line.
- Kit builds count as usage of the components. If the reorder calculation only sees the kit being sold, the cables look unused and never get reordered.
- Reserve before you build. Setting the components aside for a planned build keeps a sale from taking the last cable out from under it.
- Plan builds against free stock. A weekly list of kits to build, checked against available components, finds the missing box on Monday rather than on Friday afternoon.
Kits in StockBold
In StockBold a kit is an assembled product with a components list: one line per product in your catalogue, with the quantity the kit requires and the quantity you have assigned to it from stock. Assigned units are reserved, apart from available stock, so a sale or another job cannot take them, and two jobs counting on the same units show up at once. Components can be grouped, each group with a cost subtotal, or viewed by supplier. Larger runs are organised into projects and batches.
Completing the job takes every assigned component out of stock in one step, on the completion date, and, if you choose, brings the finished kit into stock at full cost: the components under your valuation method plus labour, overheads and other costs you add. If any component is short, completion is blocked and you see which one and by how much, with no movement recorded. A completed job can be reopened, which reverses its movements and keeps the components reserved. Components used in jobs count as usage in reorder calculations, so the cables and the boxes get their own reorder dates and alerts.
Read more about assemblies in StockBold, or the help guide on completing an assembly product.