Summary:
A tech pack, a spec sheet, and a bill of materials (BOM) are not interchangeable; each does a different job at a different sourcing stage. A factory can usually quote a rough price from just a flat sketch, a fabric spec, approximate measurements, and quantity. Sampling requires a full tech pack. Bulk production requires a sealed sample plus an approved BOM and grading rules. Sending a tech pack when a factory only needs quoting basics, or sending nothing when a factory needs a full production package, is the single most common reason small-order quotes come back wrong, delayed, or not at all.
One Sketch, Three Different Responses
A founder emails three factories with the same flat sketch and a one-line product description. One quotes back in two days. One asks for “more details” with no specifics. One never responds at all.
The sketch wasn’t the problem. The documentation behind it was. Each factory was silently judging whether enough information existed to price the job, and “enough information” means something different at the quoting stage than it does once you’re ready to cut a production run. Nobody tells you that up front, which is how tech packs, spec sheets, and bills of materials (BOM) end up being used as if they’re the same thing when they’re not even close.
This confusion shows up constantly in one specific way: a factory asks for “the BOM,” and the founder on the other end has no idea what that actually means, let alone which supplier details are supposed to go in it. Designers trained in a fashion program often hit this wall hardest; they arrive with clean, detailed flats and genuinely strong design work, but no commercial BOM, and quoting stalls immediately because a flat alone was never the document that unlocks a quote.
This guide fixes that by mapping each document to the exact stage it belongs to quotation, sampling, and production and showing you what a factory can and cannot quote from with nothing but a reference garment in hand.
The Core Problem: Three Documents, One Name
Search any of these terms and you’ll land on a software vendor’s product page or a bare glossary definition. Useful for knowing what the words mean. Useless for knowing which one to actually send to the factory this week, for this order, at this stage.
Here’s the fix: stop thinking about these documents by name, and start thinking about them by the job each one does.
- A tech pack is the full instruction manual, everything a factory needs to build a sample exactly as designed, with zero guesswork.
- A spec sheet is the measurement contract, the specific numbers a finished garment has to hit, and the tolerance it’s allowed to drift within.
- A bill of materials (BOM) is the parts list of every fabric, trim, and component in the garment, with supplier, color code, and quantity per unit.
None of the three replaces another. A spec sheet with no BOM tells a factory how the garment should measure but not what it’s made of. A BOM with no spec sheet tells a factory what goes into the garment but not what size it should come out. A full tech pack contains both, plus everything else needed to eliminate back-and-forth during sampling.
What Each Document Actually Contains
Tech Pack
The tech pack is the complete production-ready package, a technical drawing (flat sketch) from every angle, paired with every other document on this list bundled into one. A factory sampling your design for the first time should need nothing beyond the tech pack to produce a sample that matches your intent.
Spec Sheet
The measurement chart at the center of a spec sheet lists every point of measure (POM), chest width, body length, sleeve length, and hem opening against a target number and an acceptable tolerance, typically ±0.25″ to ±0.5″ at critical fit points and slightly wider elsewhere. Without this, “medium” means whatever the factory’s own block happens to produce, which varies meaningfully between manufacturers.
Bill of Materials (BOM)
A proper apparel BOM lists, line by line: the fabric (fiber content, weight, construction, supplier if known), every trim (zippers, buttons, drawcords, labels), with color codes, supplier names where applicable, and placement or usage quantity per unit. A BOM with “cotton fabric” and “zipper” as its only two lines isn’t a usable BOM. It’s a materials guess, and it’s exactly the version that gets a factory asking you for “the BOM” a second time.
Trim Sheet
Often split out from the main BOM on more complex garments, the trim sheet isolates every non-fabric component, zippers, buttons, drawcords, labels, and hang tags. with exact specs for each: size, color, material, and supplier reference number where one exists.
Construction Sheet
The construction sheet specifies how the garment is actually built: seam types, stitch types, seam allowances, and special construction callouts (reinforced stress points, specific finishing techniques). This is the document that prevents a factory’s default construction choices from silently becoming your construction choices.
Artwork Sheet
For anything printed or embroidered, the artwork sheet specifies exact placement (measured from a fixed reference point, not “centered”), scale, color values, and the decoration method itself (screen print, embroidery, or heat transfer). Vague placement instructions are one of the most common causes of the misaligned-print complaints that show up in post-fulfilment returns.
Costing Sheet
The costing sheet breaks down per-unit cost by component, fabric, trim, labor, overhead, margin, and matters most once you’re negotiating price rather than just requesting a first quote. It’s internal more often than it’s shared with a factory, but a basic version helps you sanity-check a quote that comes back.
Sample Request Form
A short cover document attached to a sample order: quantity requested, sample type (proto, fit, or pre-production), deadline, and any specific focus areas you want the factory to pay attention to. It’s the difference between “make me a sample” and a sample request a factory can actually act on without guessing your priorities.
Production Package
Once a sample is approved, the production package is everything that goes to the factory floor for the bulk run: the sealed sample itself (the physical reference standard), the approved BOM, the finalized spec sheet, and grading rules for every size in the run. This is the last documentation stage before cutting starts, and the one place where “close enough” documentation becomes genuinely expensive to fix.
Mapped to Stage: What You Actually Need, When
This is the piece missing from nearly every existing resource on this topic, not what each document is, but which one a specific sourcing stage actually requires.
Quotation Stage
A factory does not need a full tech pack to give you a rough quote. What it realistically needs: a flat sketch (even a clean hand drawing works), an approximate fabric spec (fiber content and roughly what weight; a 180 gsm cotton jersey vs. a 320 gsm fleece changes price meaningfully), approximate measurements for at least one size, and your target quantity. That’s enough for most factories to return a ballpark price range.
Sampling Stage
Sampling is where the full tech pack becomes necessary, not optional. A factory building a first sample from incomplete documentation will make its own assumptions on every gap you left open, construction details, exact trim specs, and artwork placement, and those assumptions become your sample, which you’ll then need to request revisions on, at the cost of both time and usually a second sample fee.
Production Stage
Bulk production needs the sealed sample (the physical, factory-approved reference standard every unit gets checked against), the approved BOM, the finalized spec sheet, and grading rules extending your base-size measurements across the full-size run. Nothing here should still be in flux; any open question at this stage gets baked into every single unit of the run, not just one sample.
Comparison Table
| Document | Primary Job | Needed At | Can a Factory Quote Without It? |
| Flat sketch + fabric spec | Rough pricing | Quotation | This is what quoting actually runs on. |
| Spec sheet | Defines measurements & tolerance | Sampling | Not for an accurate quote, no |
| Bill of materials (BOM) | Lists every material & trim | Sampling | Not for an accurate quote, no |
| Tech pack | Full production-ready instructions | Sampling | Not needed to quote, essential to sample correctly |
| Trim sheet | Isolates trim specs on complex styles | Sampling | No, it folds into the tech pack. |
| Construction sheet | Specifies build method | Sampling | No, it folds into the tech pack. |
| Artwork sheet | Print/embroidery placement & specs | Sampling | Only if the garment has decoration |
| Costing sheet | Per-unit cost breakdown | Negotiation | Internal, not required by factory |
| Sample request form | Defines sample order specifics | Sampling | Needed to place the sample order itself |
| Production package | Sealed sample + approved BOM + grading | Production | Required before bulk cutting begins |
What a Factory Can Quote From a Reference Garment Alone
This is one of the most common pre-sales questions, and the honest answer is more than most founders expect. If you have a reference garment, an existing piece whose fit, fabric weight, and construction you want closely replicated, a factory can often return a workable rough quote from the reference garment plus your target quantity alone, without a tech pack. The factory assesses the reference directly for fabric type, approximate construction, and trim complexity. This doesn’t replace a tech pack for sampling, but it is genuinely enough to get past the quoting stage, which is exactly where most first-timers get stuck.
One Hoodie, Three Documents: A Filled Example
Spec Sheet Excerpt (Size M, Measurement Chart)
| Point of Measure | Target (inches) | Tolerance |
| Chest width (1″ below armhole) | 22.0″ | ±0.5″ |
| Body length (HPS to hem) | 27.5″ | ±0.5″ |
| Sleeve length | 25.0″ | ±0.375″ |
| Hem opening | 19.0″ | ±0.5″ |
BOM Excerpt
| Component | Spec | Supplier/Code | Qty per Unit |
| Shell fabric | 320 gsm cotton fleece, brushed back | Mill ref #FL-320-NAT | 1.6 yd |
| Drawcord | Flat cotton, 45″ length | Trim ref #DC-45-BLK | 1 piece |
| Metal eyelets | 5 mm, antique brass | Trim ref #EY-5-AB | 2 pieces |
| Woven neck label | 1.5″ x 2″, satin finish | Per brand art file | 1 piece |
Trim Sheet Excerpt
| Trim | Placement | Color | Size |
| Drawcord | Hood casing | Black | 45″ finished length |
| Kangaroo pocket label | Inside pocket, upper right | White on black | 1″ x 1″ |
A factory receiving all three of these for a hoodie has everything needed to produce a sample with no open questions. A factory receiving only a flat sketch and the word “hoodie” has enough to quote a ballpark price and nothing else.
Who Actually Creates the Tech Pack
This is worth stating plainly because it’s genuinely unclear to most first-time founders: the brand is responsible for the tech pack, not the factory. Some factories offer tech pack creation as a paid service, and some, including Tack, offer this directly for founders who have a design but no commercial documentation experience, through our tech pack service. But a factory quoting or sampling your garment is working from documentation you provide; it isn’t the factory’s job to reverse-engineer your design intent from a rough sketch and a few text messages.
For founders coming from a design background with strong flats but no BOM, construction sheet, or spec sheet experience, this is usually the fastest unlock available; getting a professional tech pack built once removes the single biggest stall point between “I have a design” and “I have a quote I can act on.” It’s also the natural next step once you’ve decided cut-and-sew clothing manufacturing is the right production model for your garment, since a cut-and-sew factory is exactly the kind of partner this full documentation set is built for.
Frequently Asked Questions
What is the difference between a tech pack and a spec sheet?Â
A spec sheet is one component of a tech pack, specifically, the measurement chart and tolerances. A tech pack is the complete production-ready package: technical drawings, the spec sheet, the BOM, construction details, and artwork specs all bundled into one document set a factory can sample directly from.
What is a BOM in apparel?Â
A bill of materials lists every fabric and trim component in a garment, with supplier reference, color, and quantity per unit. It’s the parts list for the garment, separate from the measurements (spec sheet) and the construction method (construction sheet).
Can a manufacturer quote without a tech pack?Â
Yes, for a rough quote. A factory can typically return a ballpark price from a flat sketch, an approximate fabric spec, rough measurements, and target quantity, or from a reference garment alone. An accurate, sampling-ready quote still requires the full tech pack.
Do I need a tech pack for a sample or only for bulk?Â
You need it for the sample. A full tech pack prevents the factory from making its own assumptions on every undocumented detail, which is what usually drives a first sample needing revision. Bulk production then needs the sealed, approved sample plus the finalized BOM and grading rules on top of the original tech pack.
Who creates the tech pack, the brand, or the factory?Â
The brand is responsible for the tech pack, though some factories, including Tack, offer tech pack creation as a service for designers who have the design but not the commercial documentation experience to build one themselves. If you’re not sure where your current documentation stands, get a quote and we can tell you exactly what’s missing before you place an order.
