Tech Packs
A tech pack is the document that turns your design into something a factory can actually build. This guide covers what goes inside one, how to make a tech pack step by step, and how much detail a factory needs before it will quote or sample.
A tech pack, short for technical package, is the document that tells a factory exactly how to make your garment. It is the single spec that translates the design in your head into instructions a pattern maker, a sample room, and a production line can all work from. The tech pack meaning is literal: it packs every technical decision about a product into one reference, so the people cutting and sewing it are not guessing.
In fashion, a tech pack sits between design and production. A founder or designer owns the intent (the silhouette, the fabric, the fit), and the factory owns the execution. Without a document connecting the two, a factory has nothing to quote against and nothing to sew to. That is why the honest answer to whether a manufacturer can make clothes without a tech pack is usually no, or not the product you actually wanted. They will either decline to quote, quote high to cover their own risk, or build their best guess and send back a sample that is close but wrong.
The tech pack is also what protects you when something goes sideways. If a sample comes back with the wrong collar or a seam in the wrong place, the tech pack is the reference that settles who missed what. It is your contract in technical form, and for a founder-led brand producing on tight margins, that reference is the difference between a clean first sample and three rounds of paid revisions.
Flats, or flat sketches, are the technical line drawings of your garment shown front and back, laid flat with no body inside. They are not fashion illustrations. They show seams, stitch lines, pockets, and closures clearly enough that a pattern maker can read construction straight off the page, with callouts pointing to specific details like a bar tack here or a particular hem finish there.
The bill of materials, or BOM, lists every physical component in the garment: main fabric, secondary fabrics, thread, labels, trims, zippers, drawcords, hardware, and packaging. Each line carries a quantity, a unit of measure, a placement, and ideally a supplier and cost. The BOM is the most cost-sensitive part of the whole document, because materials are the largest line in a unit's cost, roughly 60 to 70 percent once you count trims. A missed trim or a vague fabric callout is where quotes drift and margins leak. Our bill of materials guide goes deep on how to structure one.
Points of measure, or POMs, are the measurement spec: every dimension that matters (chest width, body length, sleeve length, hem opening) with a target value and a tolerance for each. Tolerances tell the factory how much variance is acceptable before a garment is out of spec. Graded across a size run, the POMs are what make a medium a medium and a large a large.
Construction notes cover how the garment is assembled: seam types, stitch density, and print or embroidery placement. Colorways define each color combination the style ships in, tied back to specific material and trim colors on the BOM. And revision history is the quietly critical part most first tech packs skip: a dated log of what changed between versions, so you and the factory always know which spec is current. Without it, which file is the latest becomes the question that costs you a sample round.
People use tech pack and spec sheet interchangeably, but they are not the same thing. A spec sheet, or garment spec sheet, is specifically the measurement component: the points of measure, tolerances, and graded size run. It answers how big the garment is at every point. A tech pack is the full package that contains the spec sheet plus everything else (flats, BOM, construction, colorways, labels, packaging, and revision history).
Put simply, the spec sheet is one section of the tech pack. A factory can sometimes sample from a spec sheet alone when you are copying an existing garment and only changing measurements, but for a new style it needs the whole package. If you want to go deeper on building the measurement side, our garment spec sheet guide walks through POMs, tolerances, and grading.
Here is how to make a tech pack, start to finish. First, lock the design and draw clean flats of the front and back with construction visible. Second, build the BOM by listing every material and trim with quantities and placements. Third, write the measurement spec: choose your points of measure, set target values off a fit sample or a garment you already like, and add tolerances. Fourth, add construction notes and callouts. Fifth, define your colorways. Sixth, assemble it all into one document with a revision log and send.
That is the clean version. The real version is where the manual multi-tool workflow breaks. Most founders draw flats in Illustrator, keep the BOM and measurements in a spreadsheet, write construction notes in a doc, and stitch it all into a PDF by hand. A free tech pack template gets you a blank structure to fill, which helps, but you are still transcribing the same data across four tools and hoping nothing falls out of sync.
Every one of those handoffs is a place for an error to enter: a measurement typed into the spreadsheet but not the PDF, a trim color updated on the BOM but not the colorway page, a version emailed to the factory that is one revision behind the one on your desktop. None of these are dramatic mistakes on their own, but each one can turn into a wrong sample, and a wrong sample is time and money you do not get back. If your starting point is a rough drawing, our guide on turning a sketch into a tech pack covers that first mile specifically.
The Illustrator, spreadsheet, and email tangle does not just cost you hours. It costs you sample rounds. Sampling is a real line in your per-unit cost, usually in the range of 5 to 10 percent, and each extra round adds both money and weeks to your timeline. The number of rounds you run is downstream of one thing: how complete and unambiguous your tech pack was when the factory first read it.
When a factory has to guess (because a stitch type was never specified, a placement was described in prose instead of a callout, or a fabric weight was left off), it makes a reasonable assumption and samples on it. If the assumption is wrong, that is a round. Founders in early production commonly describe sending dozens of emails to resolve questions a complete spec would have answered up front. The document you thought was finished was actually a series of questions in disguise.
This is why the cheap tech pack shortcut is often the expensive one. Whether you build it yourself, use a template, or pay a freelancer, the cost that matters is not the document, it is the rework it does or does not prevent. Our guide on how much a tech pack costs breaks down freelancer, in-house, and software options, but the underlying math is the same: a complete spec pays for itself in the sample rounds you never run.
A t-shirt tech pack is the simplest common example and a good place to see the parts in action. The flats show a crew or v-neck front and back. The BOM lists the main jersey (with a weight like 180 gsm and a composition), the rib for the collar, thread, a neck label, a care label, and a hang tag. The measurement spec runs about a dozen points: body length, chest width, bottom width, shoulder, sleeve length, sleeve opening, neck width and depth, and collar height. Construction notes cover the neckline finish, the hem and sleeve hem stitch, and side seams or a tubular body.
A hoodie tech pack is the same structure with more components. The BOM grows to include the hood lining, drawcord and tipping, eyelets, ribbed cuffs and waistband, and a heavier fleece as the main fabric. The measurement spec adds hood height and width, pocket dimensions and placement, cuff and waistband height, and armhole. Construction gets more detailed: how the hood is attached, whether the kangaroo pocket is set in or patched, bar tacks at stress points, and where any print or embroidery lands.
A fleece piece, like a quarter-zip or a full-zip jacket, pushes the same document further. Now the BOM carries a zipper with a specified length, tape color, and pull, plus any bonded or taped seams and a specific fleece construction. The measurement spec covers zip length and placket, and construction notes have to be precise about seam finishing on a fabric that behaves differently from jersey. The pattern holds across all three: same anatomy for any clothing tech pack, with more detail as the garment gets more complex.
A common worry is over-speccing: do you really need to define every stitch. The practical answer is that a factory needs enough detail to quote accurately and sample without guessing, and no less. To quote, it needs the materials and construction complexity (the BOM and flats) so it can price fabric, trims, and labor. Roughly, fabric is 40 to 60 percent of a unit's cost and labor 20 to 30 percent, so anything vague in those areas is where a quote gets padded to cover risk.
To sample accurately, it needs the measurement spec, the construction callouts, and clear colorways. The test for whether your tech pack is complete is simple: could someone who has never spoken to you build the garment you are picturing from this document alone. If the answer is no, the gaps are exactly the questions you will get back by email, or worse, the places a sample comes back wrong. When you are ready to send, our guide on sending a tech pack to a manufacturer covers how to package it so quotes come back comparable instead of padded.
You do not need to specify things the factory is genuinely better positioned to decide, and a good factory will tell you where it wants a call versus where it wants a spec. But the default failure mode for new brands is too little detail, not too much. Err toward completeness on materials, measurements, and construction, and let the factory raise the handful of things it actually wants to discuss.
Building all of this by hand, across four tools, for every style and every reorder, is the work that keeps founders up the night before a factory handoff. It is also the work that does not have to be manual. Silhouet syncs your Shopify catalog in minutes, so the products you already sell come in organized instead of re-entered. From there, the AI drafts the tech pack: the spec, the BOM, the measurements, and the construction. You review and accept every part, and nothing is written to your record without your confirmation.
Because it works from structured production data rather than a lone image, the output is meant to be factory-ready, not a document that still needs the technical work done. Before you send, an AI factory-readiness check reads the tech pack the way a factory would and flags what is missing or ambiguous, so the spec gaps that cause sample rounds get caught on your side. If you are starting from a rough drawing, Silhouet can turn a sketch into a clean mockup on the same record. You can see the whole flow on the AI tech pack generator page.
And it compounds. Every product you build becomes production memory, so the next style and every reorder start closer to done instead of from a blank template. Managing every collection in one place means the canonical spec is always one click away when it is time to make the same garment again. Silhouet is free to start.
In almost all cases, yes. A factory needs a tech pack to quote a price and to sample and produce the garment you actually designed. Without one, it will either decline the order, quote high to cover the unknowns, or build to its own best guess and send back a sample that misses your intent. The rare exception is copying an existing garment closely, where a reference sample and a measurement spec can carry a lot of the load.
There is no fixed number; it depends on the garment. A simple t-shirt might need around ten to fifteen points of measure, while a structured jacket can need thirty or more. The rule is to specify every dimension that affects fit or would change the garment if the factory guessed it, give each one a tolerance, and then grade those points across your size run.
A tech pack is the technical document that tells a factory how to make a garment. In fashion it sits between design and production, translating a designer's intent into the flats, materials, measurements, construction notes, and colorways a factory needs to quote, sample, and manufacture. It is the single reference everyone works from, and the record that settles what was agreed if a sample comes back wrong.
Keep a dated revision history inside the tech pack that logs what changed between versions, and make sure the factory is always looking at the current one. The version confusion that comes from emailing PDFs back and forth is a common cause of wrong samples. A living product record, where there is one canonical spec instead of a pile of files, removes the question of which version is latest entirely.
Yes. Many founders build their first tech packs themselves using a template, drawing flats in Illustrator and keeping the BOM and measurements in a spreadsheet. It is entirely doable, but it is slow and error-prone across tools, which is why brands eventually move to a freelance technical designer or to software that drafts the structured sections for them to review and accept.
Silhouet syncs your Shopify catalog and drafts the spec, BOM, measurements, and construction for you to review, then runs a factory-readiness check before you send. Free to start.