A spec sheet, a bill of materials and a tech pack are not the same thing. A spec sheet is the measurements — the points of measure and grading. A bill of materials (BOM) is the materials list — every fabric and trim, with a cost. The tech pack is the complete document that contains both, plus flat sketches, construction notes, labels and packaging. The tech pack is the folder; the spec sheet and BOM are pages inside it.
These three terms get used interchangeably, which causes real confusion when you're talking to a manufacturer. Each one is a distinct piece of your production paperwork. Here's what each is, and exactly how they relate.
What a spec sheet is
A spec sheet (specification sheet) is the measurements. It lists every point of measure for the garment — chest, length, sleeve, and so on — with the numbers for your base size and the grading rules that scale them across the size range. It answers one question: how big is it, in every size?
What a bill of materials (BOM) is
A bill of materials is the materials list. It itemises every component — main fabric, lining, interfacing, thread and trims — each with a quantity and a cost. It answers a different question: what's it made of, and what does it cost to build? The BOM is what a factory uses to price your garment.
What a tech pack is (it contains both)
A tech pack is the whole document. It contains the spec sheet and the bill of materials, plus your flat sketches, construction notes, colorways, labels and packaging. Think of the tech pack as a folder, and the spec sheet and BOM as two of the pages inside it — both essential, neither complete on its own.
The quick mental model
Spec sheet = the measurements. BOM = the materials and cost. Tech pack = the complete package that holds both, plus everything else a factory needs.
Generate all three with AI
The good news is you don't build these separately. In Genpire, you describe your product once and it generates the spec sheet, the bill of materials and the full tech pack together — all consistent with each other and factory-ready, instead of three documents you have to reconcile by hand.
Frequently asked questions
Is a spec sheet the same as a tech pack?
No. A spec sheet is just the measurements — one section of a tech pack. The tech pack also includes the bill of materials, flat sketches, construction notes and packaging.
Is a BOM part of the tech pack?
Yes. The bill of materials is one section inside the tech pack — the costed list of every material in the garment.
Which one does a manufacturer need?
All of them — which is why you send a complete tech pack. The factory uses the spec sheet to cut to size, the BOM to price the build, and the sketches and construction notes to assemble it correctly.
Get a consistent spec sheet, bill of materials and full tech pack — generated together from one product description.
