A garment bill of materials is the single document that tells a factory exactly what to cut, sew, and finish — and what everything costs. When it is incomplete, factories either pad their quotes to cover the unknowns or come back with a list of questions that delays your critical path by days. This tutorial walks you through building a BOM that is complete enough to quote from on the first pass.
Key takeaways
- A production-ready BOM covers five categories: shell fabric, lining and interlining, trims, labels and packaging, and costing.
- Every material row needs a supplier reference, a unit of measure, a consumption figure, and a unit cost — anything missing forces a factory to guess.
- Consumption figures must account for yield loss; a flat metre-per-unit figure without a wastage allowance will produce a short-cut order.
- Keeping your BOM inside a tech pack (rather than a separate spreadsheet) reduces version-mismatch errors between design and production teams.
- PLM tools can link BOM rows to approved suppliers, so procurement always works from the same data the factory sees.
What you need before you start
- A finalised tech pack with construction details and colourways confirmed
- Approved fabric and trim samples with supplier references
- Consumption data from your pattern (or a proto-sample measurement if the pattern is not yet digitised)
- Your target FOB cost or cost ceiling
- Access to your tech pack software or PLM system
- A list of your label and packaging standards (care label content, country of origin, hang tag specs)
Step 1 — Set up your BOM structure with the right categories
Open a new BOM sheet inside your tech pack. Divide it into five clearly labelled sections: Shell Fabric, Lining & Interlining, Trims & Hardware, Labels & Packaging, and Costing Summary. Keeping these sections separate matters because factories route each category to a different department — fabric to the cutting room, trims to the sewing line, labels to finishing. A single undifferentiated list slows everyone down.
For each section, create columns for: Item Name, Supplier Name, Supplier Reference / Colour Code, Colour (per colourway), Unit of Measure (UOM), Consumption per Unit, Unit Cost, Extended Cost, and Notes. Leave the Notes column wide — it is where you record placement details, tolerance, and any approved-substitute instructions.
Note: If you are working across multiple colourways, add a column per colourway rather than duplicating rows. Factories read across a row to pick the right shade for each colour run; duplicated rows create version-control problems.
Expected result: A clean, tabbed BOM template with five sections and consistent column headers, ready to populate.
Step 2 — Populate shell fabric with consumption and yield data
For each shell fabric, enter the supplier name, their article number, the colourway reference, and the fabric width. Then enter your consumption figure — this is the metres (or yards) of fabric required per finished unit. Pull this number from your pattern marker if you have one; if not, use your proto-sample measurement and add a wastage allowance.
Yield loss on woven fabrics typically runs between 10 and 15 percent depending on pattern complexity and fabric width, and higher for fabrics with a nap or repeat. Add your wastage percentage explicitly in the Notes column so the factory can see your assumption and flag it if their equipment produces a different yield. A consumption figure without a stated wastage assumption is one of the most common causes of short-cut orders.
Enter the unit cost in the currency you have agreed with your supplier. If the cost is not yet confirmed, mark the cell clearly as ESTIMATE so the factory knows the costing summary is provisional.
Warning: Never leave a consumption cell blank. Factories will either refuse to quote or will use an industry average that may not match your design. If you genuinely do not have a figure yet, enter your best estimate and flag it.
Expected result: Every shell fabric row has a supplier reference, a fabric width, a consumption figure with wastage stated, and a unit cost (confirmed or estimated).
Step 3 — Add lining, interlining, and fusible details
Repeat the same row structure for lining and interlining. These materials are easy to underspecify because they are not visible in the finished garment, but they drive fit and hand-feel. For each interlining, record the weight (gsm), the bond type (woven, non-woven, knit), and the placement — chest piece only, full front, collar stand, cuff — in the Notes column.
For fusible interlinings, note the fusing temperature and pressure if your supplier provides them. Factories that work with multiple brands will use their own default settings unless you specify otherwise, and the wrong settings can cause bubbling or delamination in finished garments.
Expected result: Lining and interlining rows are as detailed as shell fabric rows, with placement and technical notes filled in.
Step 4 — Document every trim and piece of hardware
Trims are where BOMs most often have gaps. Work through the garment construction systematically — zip, buttons, rivets, snaps, elastic, drawcord, cord ends, velcro, shoulder pads, boning, bra underwire — and enter a row for each. For each trim, record:
- Supplier name and their part number
- Colour or finish (match to your colourway)
- Size or specification (zip length, button diameter, elastic width)
- Quantity per unit (not consumption — trims are usually counted, not measured)
- Unit cost
For zips, include the pull and slider finish separately if they are sourced independently. For buttons, record the line size (in lignes, the standard button measurement unit) alongside the diameter in millimetres — some factories work in one, some in the other.
Note: If a trim has a lead time longer than your fabric, flag it in the Notes column. Procurement needs to know which items are on the critical path.
Expected result: Every trim has a supplier reference, a specification, a per-unit quantity, and a cost. No trim is listed as TBC.
Step 5 — Specify labels and packaging
Labels and packaging are frequently left to a separate document, which means they get missed in the factory quote and then added as a change order. Include them in your BOM.
For labels, list each type separately: main brand label, size label, care and content label, country-of-origin label, and any hang tags or price tickets. For care labels, note the required language(s) and any regulatory standard the content must meet for your target market. For hang tags, note the attachment method (string, safety pin, heat seal) and the attachment point on the garment.
For packaging, record the polybag specification (gauge, size, self-seal or not), any tissue paper or stuffing, the carton spec (single or master), and any barcode or sticker requirements. Factories that pack for multiple customers need this level of detail to set up their finishing line correctly.
Expected result: Labels and packaging each have their own rows with full specifications, so the factory can cost finishing without a separate conversation.
Step 6 — Build the costing summary
At the bottom of your BOM, add a costing summary that rolls up the extended costs from each section. Your summary should show:
- Total materials cost (fabric + lining + trims + labels + packaging)
- CMT (cut, make, trim) estimate if you have it
- Target FOB
- Margin to target (or overage)
This summary is not the factory's costing sheet — it is your internal check that the materials cost is compatible with your target price before you send the BOM out. If the materials cost alone exceeds your target FOB, you need to resolve that before the factory quotes, not after.
If you are using a PLM system such as WFX or Backbone PLM (now part of Bamboo Rose), the costing summary can be linked to live supplier pricing and updated automatically when costs change — which removes the manual reconciliation step that causes most costing errors.
Expected result: A costing summary that shows whether your materials cost is compatible with your target price, before the BOM leaves your desk.
Step 7 — Embed the BOM in your tech pack and version-control it
A BOM that lives in a separate spreadsheet will drift out of sync with the tech pack. Embed it as a dedicated sheet within the same document. If you are using tech pack software such as Techpacker, the BOM and costing sheet sit alongside your spec sheets, so any change to a material is visible in context with the construction detail it relates to.
Set a version number and date on every BOM you send out. When a supplier reference changes or a trim is substituted, increment the version and note what changed in a revision log at the top of the document. Factories that receive multiple versions of a BOM without clear versioning will sometimes work from the wrong one — and you will not find out until the bulk arrives.
Note: Send the factory only the version that is approved for bulk. Keep working drafts internal. If your PLM system supports supplier portals, use them — they ensure the factory always pulls the current approved version rather than working from an email attachment.
Expected result: Your BOM is embedded in the tech pack, carries a version number, and is accessible to the factory through a controlled channel.
Troubleshooting common BOM problems
The factory comes back with a list of questions after receiving the BOM. Work through their questions and map each one to a column in your BOM. If the same question comes up more than once across factories, that column is consistently underspecified — add it to your standard template.
The bulk fabric consumption is higher than the BOM figure. Check whether your consumption figure included a wastage allowance and whether the factory's marker width matches the fabric width you specified. A fabric that arrives narrower than specified will increase consumption; document the agreed width in the BOM so there is a reference point for the dispute.
Costs in the costing summary do not match the factory's quote. Compare line by line. The most common causes are: a trim the factory sourced locally at a different price, a packaging spec they interpreted differently, or a label they included that you did not (or vice versa). A complete BOM reduces this gap; it will not eliminate it entirely because factories have their own supplier relationships and local costs.
The BOM has different colourway references to the tech pack. This happens when the BOM is maintained in a separate file. Embedding the BOM in the tech pack and using the same colour reference system throughout is the structural fix. If you are mid-season and cannot restructure, add a colourway cross-reference table at the top of the BOM.
A trim or label spec is marked TBC when the BOM goes out. Do not send a BOM with TBC items if you need an accurate quote. Either hold the BOM until the spec is confirmed, or send a preliminary BOM clearly marked as not-for-quoting and follow up with a confirmed version. Factories that quote against a TBC spec will either exclude the item or add a contingency.
What a finished BOM should look like
A production-ready BOM has no blank cells in the Supplier Reference, UOM, Consumption, or Unit Cost columns. Every section — fabric, lining, trims, labels, packaging — is populated. The costing summary shows a materials total that you have checked against your target price. The document carries a version number and is embedded in, or explicitly linked to, the tech pack it belongs to. When a factory opens it, they should be able to begin quoting without sending you a single question.
FAQ
What is a garment bill of materials? A garment BOM is a structured list of every material, trim, label, and packaging component needed to make a finished garment, with quantities, supplier references, and unit costs. It is typically a page within the tech pack and is the primary document factories use to quote and procure.
How is a BOM different from a tech pack? A tech pack is the full set of production documents — construction details, measurements, grading, artwork, and the BOM. The BOM is one sheet within the tech pack, focused specifically on materials and costs rather than construction instructions.
What unit of measure should I use for fabric in a BOM? Use the unit your supplier quotes in — usually metres or yards — and state the fabric width alongside it. Be consistent across all fabric rows; mixing metres and yards in the same BOM causes quoting errors.
How do I calculate fabric consumption for a BOM? Pull the consumption figure from your pattern marker if available. If not, measure the fabric used in your proto-sample and add a wastage allowance — typically 10–15 percent for wovens, more for fabrics with a repeat or nap. State the wastage percentage explicitly so the factory can verify it against their own marker.
Should packaging be included in the garment BOM? Yes. Packaging is part of the total cost of a finished unit and needs to be costed and specified. Leaving it out means the factory either excludes it from their quote or makes assumptions about spec that may not match your requirements.
Further reading
- The Ultimate Guide to Bill of Materials in Fashion — Techpacker
- Tech Pack BOM: Bill of Materials Guide — Fashion Index
- What is the BOM for a Fashion Tech Pack? — 383 Design Studio
- A Guide to the Bill of Materials in the Fashion Industry — NetSuite