What it is
A bill of materials (BOM) is a structured list of every component, material, and sub-assembly needed to make one unit of your product. It usually includes part names, quantities, specifications, and sometimes supplier or part numbers.
Factories use the BOM to estimate material cost, lead time, and assembly complexity. Without it, quotes are guesses and scope disputes become more likely later.
What to include for UK sourcing
For UK manufacturing quotes, aim for a BOM that is versioned (for example “BOM v1.2”), lists units clearly (each, kg, metres), and calls out anything safety- or compliance-related (for example finishes, coatings, or regulated components).
If you are still iterating, say so explicitly and separate “confirmed” lines from “TBC” lines so everyone understands what might change.
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