Garment Bill of Materials: What It Is and Why Quotes Disagree Without One
A garment bill of materials, usually shortened to BOM, is the list of every material that goes into one style: the main fabric, the rib, the thread, the drawcord, the labels, the hangtag and the packaging. If you are holding two quotes that do not match, ask whether both suppliers priced the same list. A bill of materials for clothing turns an opinion about what the garment contains into a checkable document, and it is the main reason one factory looks cheaper than another.
The BOM is not a design document and not a price list. It sits between the tech pack, which shows how the garment is made, and the costing sheet, which puts a price on each line. Our guide to what a tech pack contains explains the first of those.
What Goes Into a Garment BOM
A garment BOM is built from groups of materials, and each group fails in its own way when it is left out. The groups below cover most woven and knitted casualwear, and the order is the one most factories use.
Fabric lines
Main fabric, contrast fabric, rib, lining and pocketing each get their own line, with composition, weight, construction, finish and cuttable width. Rib is a separate fabric with its own composition, so never fold it into the body fabric line.
Sewing and structure
Thread, interlining, tape, elastic and any stiffeners belong here. They are small lines but they affect durability and stitching, and a factory that substitutes thread without telling you changes the product.
Trims and hardware
Zips, buttons, snaps, eyelets, drawcords and cord ends are trims. Give each one a size, a material, a finish and a colour reference, because trims have their own suppliers and their own lead times.
Labels, tags and packaging
Main label, care and size label, hangtag, polybag, tissue, cartons and any stickers complete the list. Packaging often decides whether a shipment is accepted by a retailer or a warehouse, so it deserves the same detail as the fabric.
Materials also affect what happens at the border. The fibre content and construction of each fabric feed into how the finished garment is classified for import, so keep the composition on the list exact and check the current duty and classification for your product in the UK Trade Tariff before you finalise a landed cost.
A Worked Garment Bill of Materials for a Hoodie
The example below shows how a garment bill of materials looks for a single pullover hoodie. Every figure is illustrative and the supplier column shows who is responsible for sourcing each line. Use it as a layout, not as a specification.
Illustrative BOM: pullover hoodie, one size, one colourway
| Item | Specification | Supplier | Quantity | Unit |
|---|---|---|---|---|
| Body fabric | 80/20 cotton-polyester brushed fleece, 320 GSM, 150 cm cuttable width | Factory-sourced | 1.155 | m per garment (gross) |
| Rib | 1x1 cotton-elastane rib for cuffs and hem, colour-matched | Factory-sourced | 0.25 | m per garment |
| Sewing thread | Polyester core-spun, colour-matched to body | Factory | 220 | m per garment |
| Drawcord | Flat cord, 140 cm, finished ends | Factory-sourced | 1 | pc |
| Eyelets | Metal, matching finish, agreed inner diameter | Factory-sourced | 2 | pcs |
| Main label | Woven neck label, brand artwork approved | Brand-nominated | 1 | pc |
| Care and size label | Printed, sewn into side seam | Brand artwork, factory made | 1 | pc |
| Hangtag | Card tag with string and barcode sticker | Brand-nominated | 1 | pc |
| Polybag | Clear bag with printed warning where required (check current rules) | Factory | 1 | pc |
| Carton | Outer carton, one per 20 garments | Factory | 0.05 | pc per garment |
Illustrative only. Fabric quantity is the gross figure from the consumption example further down this page. Every specification should be replaced with your own.
Count the lines: ten items for one plain hoodie, and only the first two are fabric. That is why a quote based on fabric alone leaves out a surprising number of purchases. Each of those purchases has to be ordered, received, checked and delivered to the sewing line on time, and a single late label can hold up a finished garment just as surely as a late fabric.
Share of BOM lines by type, illustrative hoodie
Count of lines, not share of cost
- Main fabric10%
- Rib10%
- Drawcord and eyelets20%
- Sewing thread10%
- Labels and tags30%
- Packaging20%
Illustrative. The chart counts how many of the ten lines in the worked example belong to each group; it does not show cost. Small lines dominate the list, but fabric usually dominates the spend.
The split shows why the BOM must be complete before costing. Labels and packaging make up half of the lines in this example, and each is a separate purchase with its own minimum and lead time.
How to Write Quantities, Units and Tolerances
A quantity without a unit is a guess, and a quantity without a tolerance is an argument waiting to happen. Write each line with a net quantity (what the garment needs), a wastage allowance (what is lost in cutting and sewing) and a gross quantity (what must be bought). Then multiply by the order quantity.
Illustrative consumption arithmetic for the body fabric
| Step | Calculation | Result |
|---|---|---|
| Net fabric per garment | From the marker or pattern layout | 1.1 m |
| Wastage allowance | An assumed allowance of 5%, agreed with the factory | + 0.055 m |
| Gross fabric per garment | 1.1 x (1 + 0.05) | 1.155 m |
| Fabric for an order of 500 | 1.155 x 500 | 577.5 m |
Illustrative assumptions: net 1.10 m, a 5% allowance and an order of 500. Real allowances depend on the fabric, the marker and the factory, so ask them to state theirs.
Quantities are also where a cheap quote often hides its saving: a supplier who assumes a lower allowance or a narrower garment size range will show a lower fabric cost, and the difference reappears later as a price increase or a shortfall. Ask every supplier to state the net figure and allowance they used. Keep units consistent across the list: metres for fabric, pieces for trims and labels, and a clear statement when something is bought by weight. Where a trim must match a colour or size exactly, say so in the specification and state the tolerance, for example how far a drawcord length can differ. For wider cost context, see our clothing manufacturing cost guide.
Bill of Materials, Tech Pack and Costing Sheet: How They Fit Together
Brands often ask whether the BOM replaces the tech pack. It does not; the three documents answer different questions, and each depends on the others.
Three documents, three jobs
| Document | Answers | Main user | Depends on |
|---|---|---|---|
| Tech pack | How is the garment drawn, measured and made? | Pattern maker and sewing line | Design and measurements |
| Garment bill of materials | What materials, in what quantity, from whom? | Sourcing and costing | The tech pack |
| Costing sheet | What does each line cost, and what is the total? | Buyer and factory | The bill of materials |
A general division of labour. Some factories combine the BOM and costing sheet, but the list of materials should still be a separate, checkable section.
When the BOM changes, the costing sheet must change with it. Our jeans costing sheet guide shows how a materials list feeds a price, and our pattern maker guide explains how the pattern behind the net fabric figure is produced.
Common Omissions That Make Quotes Differ
Most BOM errors are omissions rather than mistakes. The items below are the ones that most often appear in the final garment without appearing on the list.
Check these before you send a BOM for pricing
- Rib or secondary fabric, listed on its own line with its own composition
- Thread type and colour, including any contrast stitching
- Pocket bags, linings and interlinings that the customer never sees
- Drawcord ends, eyelets, zip pullers and other small hardware
- Care label, size label and country-of-origin information, as required
- Hangtags, barcode stickers, strings and any swing-tag fasteners
- Polybags, tissue, inner packs and outer cartons
- Test or certificate needs, such as a material or chemical certificate
Not exhaustive. Ask the factory to add any line they expect to buy that is not on your list.
Certificates deserve a mention here. If you need to show that a fabric or trim meets a safety or chemical standard, put the requirement on the line, because the certificate belongs to a material, not to a garment. Check what a scheme such as OEKO-TEX actually covers before you rely on it.
Keep the Garment BOM Version-Controlled
A BOM changes through development: a rib is swapped after a fit sample, a trim is substituted because of a lead-time problem, a label is redesigned. If nobody records the changes, bulk production starts from an old list. Treat the BOM as a document with a version number, a date and an owner, and approve each version before the next sample is made.
A simple version log
| Version | Stage | What changes | Approved by |
|---|---|---|---|
| v1 | Proto sample | First material list from the tech pack | Brand and factory |
| v2 | Fit sample | Rib and drawcord confirmed after fit comments | Brand |
| v3 | Pre-production sample | Labels, hangtag and packaging added and approved | Brand |
| v4 | Bulk | Quantities fixed for the confirmed order; locked version | Brand and factory |
An example of one way to record versions. Use your own stage names and keep the dated files.
How many sample rounds you need affects how often the BOM is revised, and our guide to clothing sample cost explains what drives the number of rounds.
Building Your Garment Bill of Materials in Five Steps
You do not need specialist software to start. A spreadsheet with the five columns shown earlier is enough, as long as you build it in a fixed order.
From tech pack to approved BOM
- 1List every partGo through the tech pack and the finished garment, piece by piece.
- 2Write each specificationGive each line a material, size, finish and colour reference.
- 3Add quantity and unitShow net, allowance and gross, with a clear unit.
- 4Assign a supplierMark each line as factory-sourced or brand-nominated.
- 5Version and approveDate it, number it and have both sides confirm it before costing.
A general path for a first BOM. Complex garments will have more lines but the same sequence.
Ask the factory to return the BOM with their own additions marked, rather than a fresh list in their format. That way you can see exactly what was missing and what the factory assumed.
What to Ask a Factory About Your Bill of Materials
A good factory will challenge your BOM rather than accept it. Ask whether any line is unavailable at your quantity, whether a substitute is proposed, and who is responsible for each purchase and for any minimum order that applies. Ask also how the factory handles a material that arrives late or fails a test, because that decides who pays and who waits.
Ask the factory: "What else do you expect to buy for this style that is not on my list?" Their answer is often a line you forgot, and it costs nothing to ask.
Which line on your current garment bill of materials is least certain: the fabric, a trim, or the packaging? Fix that line first, because it is the most likely source of a quote you cannot compare.
How Ruhrose Approaches the Bill of Materials
Ruhrose develops hoodies, fleece, jersey, denim and woven casualwear in Bangladesh, with UK buyer support. We expect a BOM to be built and revised alongside the samples, and we mark what we have added so you can see the difference from your original. If you are still deciding on a first order, our guide to how to write a clothing RFQ is a sensible next step, and you can learn about Ruhrose clothing manufacturing services on our homepage.