A bill of materials is only useful when it is complete and correct. When it is not, the factory fills in the blanks — and the blanks it fills in are rarely what you intended. The seven errors below account for a large share of the re-orders, production holds, and late shipments that production teams deal with every season. Each one is preventable with a straightforward fix.
Key takeaways
- Missing trim quantities are the single most common reason a factory substitutes a component without telling you.
- Fabric width stated incorrectly can inflate or deflate your yardage requirement enough to cause a fabric shortage mid-cut.
- A BOM without colour callouts leaves the factory guessing, and guessing costs you time and money.
- Packaging that is listed but not costed creates budget surprises at the final landed-cost stage.
- A BOM is a living document — it should be version-controlled and updated every time a component changes.
Why do BOM errors cause so many production problems?
The BOM is the single source of truth that travels from your design team to your factory. When a detail is missing or wrong, the factory either stops and waits for clarification — adding days or weeks to your timeline — or makes a substitution that may not meet your quality or compliance standards. As Techpacker's BOM guide explains, the materials sheet needs to capture not just what a component is, but its quantity, placement, colour, supplier reference, and cost. A gap in any of those columns is a gap the factory will interpret on its own.
The fixes below are written for production coordinators, tech pack managers, and anyone who signs off on a BOM before it leaves the building.
The 7 errors — and how to fix them
1. Missing trim quantities
A BOM that lists a zipper, a button, or a label without specifying how many are needed per garment is an invitation for the factory to order whatever quantity feels right. Trims are frequently under-ordered as a result, and a shortage of something as small as a hang tag can hold an entire shipment.
The fix: Add a "quantity per garment" column to every trim row, and a separate "total quantity" column that multiplies by your order size. Audit this column every time the design changes — a style that gains a second pocket gains a second set of rivets too. The Fashion Index BOM guide recommends breaking trims into their own section of the BOM, distinct from shell fabrics, so they are harder to overlook during review.
2. Wrong fabric width
Fabric width determines how many pattern pieces fit across a single lay, which determines how many metres or yards you need to cut your order. If your BOM states 150 cm width but the fabric your supplier ships runs at 140 cm, your marker is suddenly wrong and your yardage is short.
The fix: Confirm the fabric width with your supplier before you finalise the BOM — not after. State the width as a range if the supplier cannot guarantee a single figure (e.g., "140–145 cm usable width"). Flag any style where the marker efficiency changes materially if width drops by even 5 cm, and build a small buffer into your yardage calculation. If you are working in a PLM platform such as BeProduct, link the confirmed supplier spec sheet directly to the material record so the width on the BOM always traces back to a document, not a memory.
3. Absent or ambiguous colour callouts
A BOM row that reads "thread — beige" tells the factory almost nothing. Which beige? Against which swatch? Thread, lining, and interlining colours are frequently mismatched in production because the BOM was written in plain language rather than referencing a colour standard.
The fix: Every colour-carrying component on your BOM should reference a colour standard — a Pantone code, an internal colour library reference, or a physical swatch number — not a descriptive word. For components that need to match the shell fabric (zip tape, binding, topstitching thread), note "match to shell" explicitly and attach the shell swatch reference. 383 Design Studio's BOM explainer makes the point clearly: a BOM is only as useful as the specificity of its callouts.
4. No placement or construction notes on trims
Knowing that a label exists is not the same as knowing where it goes, how it is attached, or at what height it sits from the hem. Without placement information on the BOM, factories default to their own standard — which may not match yours.
The fix: Add a "placement / construction note" column to your trim rows. For a main label: "centred at CB neck seam, sewn on all four sides." For a woven patch: "3 cm above left hem, heat-applied then bar-tacked at corners." If the placement is complex, reference the relevant tech pack page number so the factory can cross-check. This is especially important for branded hardware and labels, where incorrect placement can trigger a quality rejection.
5. Fabric consumption calculated without shrinkage or waste allowance
Raw yardage calculated directly from the pattern area, without accounting for shrinkage after washing or finishing, and without a cutting waste factor, will almost always leave you short. The shortfall may not appear until mid-production, at which point re-ordering fabric and waiting for it to arrive is the only option.
The fix: Build two adjustments into your fabric consumption figure: a shrinkage factor (obtained from your fabric test reports) and a cutting waste factor (typically expressed as a percentage of the marker efficiency). Document both figures in the BOM so anyone reviewing it can see how the final yardage was reached. If you do not yet have test data for a new fabric, use a conservative estimate and flag it as provisional — a note in the BOM is far cheaper than a fabric shortage. NetSuite's overview of BOM management in fashion describes the BOM as a living document precisely because figures like these need to be updated as real data comes in.
6. Packaging listed but not costed
Packaging — polybags, hangers, hang tags, stickers, carton specifications — appears on many BOMs as a list of items with no unit cost attached. When the final landed cost is calculated, packaging is either estimated loosely or omitted, and the actual cost comes as a surprise.
The fix: Treat packaging components exactly as you treat fabric and trims: each line gets a unit cost, a supplier reference, and a quantity per garment. If you are building a cost sheet alongside your BOM, pull the packaging lines through to it. This is also the point at which to confirm whether the factory is supplying packaging or whether you are — a question that is often left unanswered until the order is already in production.
For teams using AI visual tools like Caimera to generate product photography or catalogue imagery before manufacturing, the packaging spec on the BOM is also what determines how the product will appear in those images — a polybag that is not yet specified cannot be rendered accurately, which creates a feedback loop worth closing early.
7. No version control on the BOM
A BOM that is emailed as a flat file, revised locally, and re-sent without a version number is a BOM that will eventually be confused with an earlier draft. Factories have gone into production on superseded BOMs more times than anyone in the industry likes to admit.
The fix: Every BOM should carry a version number and a date in its header. When a component changes — a fabric is substituted, a trim is discontinued, a colour is updated — the BOM gets a new version number and the change is logged in a revision history, even if that history is just a single column at the bottom of the sheet. If your team is working in a PLM system, version control is typically handled automatically; if you are working in spreadsheets, make the version discipline explicit in your team's workflow. The goal is simple: anyone who picks up the BOM should be able to tell immediately whether they are looking at the current version.
How do you build a BOM that avoids these errors from the start?
The most reliable approach is to treat the BOM as a structured template rather than a free-form document. A good BOM template includes mandatory columns for quantity, colour reference, supplier, unit cost, and placement notes — so the person filling it in cannot skip a field without it being obvious. Reviewing the BOM against the tech pack before it leaves the design team catches the majority of errors listed above before they reach the factory.
For teams managing large product ranges, centralising BOM data in a PLM platform — BeProduct is one option built specifically for fashion teams — means that when a material changes, every BOM that references it can be updated from a single record rather than hunted down across dozens of spreadsheets.
FAQ
What is the most common BOM error in apparel production? Missing or incomplete trim quantities are the most frequent issue. When a factory cannot find a quantity on the BOM, it either orders a round number or waits for clarification — both outcomes slow production.
How often should a BOM be updated? Every time a component changes: fabric substitution, trim discontinuation, colour update, or packaging change. Each update should carry a new version number so the factory always knows which BOM is current.
What is the difference between a BOM and a tech pack? A tech pack is the full product specification document — it includes measurements, construction details, grading, and fit comments. The BOM is one page within the tech pack that lists every material and component, with quantities and costs.
Should packaging be included in the BOM? Yes. Polybags, hangers, hang tags, stickers, and carton specs should each have their own BOM line with a unit cost and supplier reference. Leaving packaging off the BOM is one of the most common causes of landed-cost surprises.
How does fabric width affect BOM accuracy? Fabric width determines how many pattern pieces fit across a lay, which sets your yardage requirement. If the width stated on the BOM differs from what the supplier ships, your marker efficiency and total consumption figure are both wrong — usually resulting in a fabric shortage.
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