What is a tech pack? What goes in one and how to write it

What a tech pack does

A tech pack turns a design into instructions a stranger can follow. The pattern maker cuts from it, the sample room sews the first prototype from it, and the costing team prices fabric, trims and labor from it. When the bulk order arrives, the inspector checks the garments against it.

That last job is the one founders underestimate. If a hem length, a stitch type or a trim color is not written down, the factory is not wrong when it chooses for you. A tech pack is how you make "not what I asked for" a claim you can prove.

It is not a mood board or a single sketch, and it is not a pattern file, although the pattern is built from its measurements. One tech pack covers one style. Colorways of the same style can share it; a new fit or fabric needs its own.

What goes in a tech pack

The bill of materials and the measurement chart do most of the work. A factory can live without polished sketches; it cannot price a garment whose fabric weight, composition and construction are missing.

Tech packs are usually written by a technical designer, either on staff or freelance, and sent to factories as a PDF or spreadsheet, with the artwork as vector files. You can write your first one yourself if you can measure a garment and describe how it is sewn; the table above works as a blank template, one page per section.

What a points-of-measure chart looks like

Point of measure	How to measure	Target	Tolerance
Body length	High point of shoulder to hem, garment flat	29 in	± 1/2 in
Chest width	1 in below the armhole, edge to edge	21 in	± 1/2 in
Sweep width	Along the hem, edge to edge	20.5 in	± 1/2 in
Shoulder width	Shoulder seam to shoulder seam	18 in	± 3/8 in
Sleeve length	Shoulder seam to sleeve hem	8.5 in	± 3/8 in
Sleeve opening	Across the sleeve hem, flat	7 in	± 1/4 in
Neck width	Neck seam to neck seam at the shoulder	7.5 in	± 1/4 in
Front neck drop	High point of shoulder to the neck seam at center front	3.5 in	± 1/4 in
Neck rib height	Finished rib, seam to edge	0.75 in	± 1/8 in

Illustrative figures, not a quote. Real prices depend on the spec, quantity and factory.

Every row names where the tape starts and stops. "Chest" alone gets measured a different way by each person who picks up the tape; "one inch below the armhole, edge to edge" gets measured the same way every time.

The label rules your tech pack has to carry

For garments sold in the US, the label spec is not a style choice. The Federal Trade Commission's textile rules require the fiber content as generic fiber names with the percentage of each by weight, in descending order of predominance^[1]. A fiber that makes up less than 5%^[1] of the fiber weight is normally shown as "other fiber" rather than by name, unless it does a job at that amount, such as a little spandex added for stretch, and wool must be named with its percentage even below that level^[1].

Take the composition from the mill's fabric specification and test the bulk fabric if you can. The FTC allows a tolerance of 3%^[1] on fiber content claims, and it treats a bigger gap as mislabeling. A guess in the tech pack becomes a false label on every unit.

The label also has to identify the company name or the FTC Registered Identification Number (RN) of the manufacturer, importer or another business that markets or handles the product^[1]. For an imported line that is usually your own company, so decide whether you print your full business name or an RN before the label artwork goes to the factory.

Where the label goes is specified too. On a garment with a neck, the country of origin label goes on the inside center of the neck^[1], so put the label position in the tech pack, not only the label artwork.

Care labels follow a separate FTC rule. They have to be attached permanently and securely, and legible for the useful life of the product^[2], and every care instruction needs a reasonable basis, meaning reliable evidence^[2] that the garment survives it. If your fabric bleeds or your trim cannot take a dryer, write the care instruction from a wash test on the sample, not from a template.

Fabric construction sets the tariff chapter

The tech pack also decides how the garment is classified at the border. Most knitted or crocheted apparel falls in HTS chapter 61^[3], and most apparel that is not knitted or crocheted falls in chapter 62^[4]; a few product types, such as bras, have their own heading whatever the fabric. Within a chapter, fiber content splits the lines further: the heading for knitted T-shirts, for example, has separate subheadings for knitted T-shirts of cotton and of man-made fibers^[5].

So "cotton blend top" is not enough. Write "single jersey knit, cotton and elastane, with the percentage of each" and the fabric weight, and your customs broker can classify it before you order. That classification is what sets your import duty rate.

Children's clothing: drawstrings and tracking labels

If you make kidswear, the construction section carries a safety rule. The Consumer Product Safety Commission treats children's upper outerwear in sizes 2T to 16^[6] that has drawstrings and does not conform to ASTM F1816-97^[6] as a substantial product hazard. The standard covers hood and neck drawstrings up to size 12, and waist and bottom drawstrings across the whole range^[6]. The simplest spec is no drawstrings at the hood, neck, waist or hem in children's sizes; if a design needs one at the waist or hem, write the standard's requirements into the construction page and have the factory confirm them in writing before the first sample.

Children's products also need permanent, distinguishing marks on the product and its packaging^[7], to the extent practicable, identifying the manufacturer or private labeler, where and when they were made and in which batch. Add the tracking label's content and position to the label page.

How to write a tech pack, step by step

1. Start from a garment you have measured. Pick a reference piece whose fit you like, measure it flat and note what you want changed. It is faster than inventing a fit from nothing.
2. Draw the flats. Front and back views with every seam, pocket, closure and trim, plus close-ups of anything unusual.
3. Build the bill of materials. For each fabric give the construction (knit or woven), composition by fiber, weight and finish. For each trim give size, material and color reference. Add labels, hangtags and packaging.
4. Write the measurement chart for one base size. Name each point of measure, describe how to measure it and set a tolerance you will actually enforce.
5. Add grade rules for the other sizes, or ask the factory to propose them and approve them in writing.
6. Specify construction. Seam types, stitch types and density, seam finishes and hems. If you do not know the terms, mark the reference garment's seams and photograph them.
7. Fill in the label and packaging page with the fiber, care, origin, company or RN and size content above, where each label sits, and how the garment is folded and packed.
8. Version it and send it with your request for quotes. Put the revision number on every page. After each sample, log the fit comments and issue the next revision rather than emailing loose changes.

What a tech pack changes on a quote

A factory prices what the tech pack says. With a full bill of materials and construction page, it can work out fabric consumption, trim cost and sewing time, and two factories are pricing the same garment. Without one, each factory fills the gaps with its own defaults, and the cheapest quote is often the one that assumed the lightest fabric.

The same spec is what a quality inspection measures the bulk order against, so the time you spend on tolerances pays back when the production run lands.