What is a Bill of Materials (BOM) in Fashion? 2026 Guide

A bill of materials, or BOM, is the itemized list of every physical component that goes into making one garment. In fashion, the BOM is the page inside the tech pack the factory uses to source, quote, and inventory the run. If the BOM is wrong, the quote is wrong, and the bulk order is wrong.

What goes in a fashion BOM

A complete fashion BOM lists, for every component:

• Item name, e.g. "main shell fabric", "interior label", "YKK #5 zipper"
• Supplier, mill or trim vendor, with article number
• Composition, fiber content, weight, finish
• Color, Pantone or supplier color code
• Placement, where on the garment
• Consumption, meters of fabric, units of trim per garment
• Cost, landed unit cost

BOM vs tech pack vs trim card

Three documents that are often confused:

The BOM lives inside the tech pack as one page. The trim card is the physical version of the trim rows of the BOM, sent to the factory so they can match by hand.

Why brands get the BOM wrong

The most common BOM mistakes that cost real money:

1. Missing thread spec, factory uses default, topstitch color is off.
2. One BOM for every colorway, works until you have a contrast trim, then breaks.
3. No consumption per garment, factory cannot quote without it, leads to padded quotes.
4. Generic supplier names, "metal zipper" instead of "YKK 5VS auto-lock" lets the factory substitute.
5. Out-of-date trim article numbers, trim discontinued, factory substitutes, brand never approves.

How AI generates the BOM

Building a BOM by hand for one garment takes 1-2 hours in Excel. For a 20-style capsule that is 20-40 hours of typing supplier codes and placement notes. AI fashion workflow software like The F* Word now generates the BOM page directly from a flat sketch plus the brand's trim library, in minutes as part of a full 8-10 minute tech pack run. The system validates that every trim referenced in the flat exists in the BOM and that every BOM row has supplier, color, and consumption filled.

How factories use the BOM

The factory takes the BOM and does three things: (1) requests fabric and trim samples from the listed suppliers; (2) produces a costed quote based on consumption and supplier prices; (3) uses the BOM as the QC checklist for incoming materials. A clean BOM means a clean quote and a fast counter-sample.

FAQ

Does every garment need its own BOM?

Yes, even when two styles share a fabric. Trims, thread, and labels differ by style.

Should the BOM include packaging?

Yes. Polybag, hangtag, sticker, and inner carton spec all sit on the BOM.

BOM vs costing sheet, same thing?

No. The BOM is materials. The costing sheet adds labor, factory margin, freight, and duty to land at FOB or landed cost.

The four BOM views every factory needs

A useful BOM is not one table, it is four views of the same data:

1. Sourcing view, sorted by supplier, used to send purchase orders.
2. Placement view, sorted by location on the garment, used by the cutting and sewing lines.
3. Costing view, sorted by unit cost, used to calculate landed FOB per garment.
4. QC view, sorted by inspection point, used at incoming materials check.

Most templates only produce the sourcing view. Factories that work with sophisticated brands expect all four. AI workflow tools auto-generate each view from the same underlying BOM row data.

BOM consumption math, worked through

Consumption is the meters of fabric or units of trim needed per garment. For a women's size medium shirt with 1.5m fabric at 150cm width, marker efficiency at 82%, and a 4% allowance for fabric flaws, the BOM line reads 1.5m × (1 ÷ 0.82) × 1.04 = 1.90m per garment. Skip the marker efficiency and the factory pads your quote with their own assumption, usually 75%, costing you 9% per unit on fabric.

Trims your BOM is probably missing

Five trim categories brands forget on the first BOM revision:

• Interfacing or fusing, different weights for collar vs cuff vs placket.
• Bar tacks and rivets, placement and quantity per garment.
• Care label and content label, separate items, different suppliers.
• Hangtag string or pin, small line item but absent on day-one BOMs.
• Inner polybag size, incorrect size leads to repackaging at the warehouse.

BOM in PLM systems vs Excel vs AI workflow

PLM systems like Centric and PTC FlexPLM store the BOM in a structured database, which is great for enterprise reporting but heavyweight for small teams. Excel is fast to start with and impossible to scale past 30 styles a season because version control breaks. AI workflow tools sit in between: structured data that round-trips to the factory PDF, with the brand's trim library as the source of truth so the same YKK zipper is always identified the same way across every BOM.