How to write a tech pack, step by step

This is the method: what to do first, what to measure, and which fields can only be written once the factory has made something. The contents list itself is covered separately, and what a pack is for is here.

One principle runs through it. A pack is a document about a garment, and the garment does not exist yet. So the pack is built in passes, each one adding a layer of certainty, and the passes have an order because some fields depend on others.

Quick answer: build it in six passes

Passes one to three are the ones a factory cannot start without. Passes four and five are needed before the sample is made, because they change the operations. Pass six can wait until just before freight, and should not wait longer.

Pass 1: identity, and the base size

Write down the style name, the season, the date, and — this is the one people forget — the size the chart will describe. A measurement chart for a size S and one for a size M look identical without that line, and the difference matters to the pattern maker reading it.

• One name, used consistently. The style name in the pack should match the name in the order and the correspondence. Two names for one garment is how files get lost.
• The base size, stated. Everything in the chart is relative to it.
• A version number and date, from the first draft. Versioning is not something you add once the pack is finished; it is what makes the finished pack trustworthy.

Pass 2: flats

Draw the garment flat, from the front and the back, with the seams where they actually run. This is a technical drawing, not an illustration — mood is somebody else's document.

• Front and back, always. The back carries closures, yokes and often the only place a fit problem shows.
• Seams and darts drawn, not implied. A dart is how a bodice takes shape; if it is not on the drawing it will be guessed at.
• Callouts for anything unusual — an asymmetric hem, a hidden placket, a drape that starts at the shoulder.
• Separate drawings for separate components — lining, facing, belt, tie — each with its own shape.

If you are working from a reference garment rather than a design, the flats come from measuring and drawing that garment, minus the changes you intend. Drawing what you want, rather than what the reference is, is the whole point of the pass.

Pass 3: the measurement chart

This is the pass that turns the garment into numbers, and it is where most of the value sits. It is also the pass where working from a physical reference is worth far more than working from a photograph.

Measure the way the factory will

A garment laid flat and a garment measured on a curve give different numbers for the same point. A neckline depth measured from the shoulder seam and one measured from the high point of shoulder differ by a centimetre. Neither is wrong, and a chart that does not say which method applies will be measured both ways, and then disputed.

• State flat or on-curve for every point where it matters.
• Name the origin for every length — centre back neck, natural waist, high point of shoulder.
• Give circumference or half-measure consistently, and say which.

Tolerances are not optional

A target without a range can only be disputed. With a range it becomes something that passes or fails, which is the difference between an inspection and an argument. The range should be tight enough to protect the fit and wide enough to be achievable in the chosen cloth, and the factory can advise on the second half of that.

Pass 4: describe the inside

Anything a customer cannot see belongs here, and it is the section most packs under-write because the writer has been looking at the outside of the garment throughout the design process.

• Lining — full, half or none, in what, and how it is attached at the hem, the armhole and the waist.
• Structure — interlining, stay tape, boning, and where each one goes.
• Closure — type, length, position, and what conceals it.
• Seam and edge finish — the method and the hem depth.

The test for this pass is simple: could somebody build the garment from this section without seeing the design? If not, it is a description rather than a specification.

Pass 5: materials and trims

Name the fabric as precisely as you can, and describe its behaviour where you cannot name it. Name the trims by type, size, finish and position. This pass is short and it is where a surprising amount of the calendar is decided, because trims are ordered by the hundred and carry their own lead time.

Where a substitution would be acceptable, say so and state the boundary — colour, weight, stretch and recovery within range. Where it would not, say that instead. An unstated policy becomes an assumption at the point a cloth is unavailable.

Pass 6: finish, labelling and packing

The last pass, and the one that can safely be written while the sample is being made. State the care and content labelling for the destination market, the brand label placement, the folding and bagging, and the carton specification. None of it affects the garment, and all of it affects whether the goods can be sold where you intend and whether the freight is charged on actual or volumetric weight.

The only rule about timing is that it must be settled before freight is booked. Everything else in the pack has a deadline that moves as the garment moves; this one has a deadline created by the shipping document.

What can wait, and what cannot

The pattern in that table is that each field's deadline is set by whatever reads it next. A field nobody reads until shipping has a late deadline; a field the pattern maker needs has a deadline before the pattern exists, which is generally earlier than people expect.

This is also the answer to the question buyers ask most often — whether a pack has to be finished before anything starts. It does not. It has to be finished before the stage that depends on it, and those stages arrive in a known order.

Manufacturing perspective: how a first draft is read

A factory reading a first draft is looking for what is missing rather than what is there, and it usually looks in this order.

1. The base size, first. Without it, the chart cannot be interpreted, and the pattern maker will assume one.
2. The measurement method, second. This is where a chart that looked complete turns out to be ambiguous.
3. The fabric, third. Without it, the construction cannot be costed and the sample cannot be made in the right material.
4. The construction, fourth. Not to check whether it is detailed, but to find the two or three places where it will fight back.
5. Everything else, in whatever order it appears. Packing and labelling are read by whoever is booking the freight, not by the sample room.

The practical consequence is that a pack should be ordered for the reader rather than for the writer. Putting the base size and the measurement method at the top of the chart costs nothing and removes the two most common round trips.

Keeping one version of the truth

A pack that is edited in place is worse than no pack, because it gives two people the same confidence about different documents. The discipline is small and it is the difference between a specification and a suggestion.

• Date and number every issue. Version 3 supersedes version 2, stated explicitly inside the document.
• Never edit a previously issued version. Issue a new one, and say what changed.
• Circulate to everyone who holds a copy, and expect the same in return.
• Keep the approved version separately. The approved pack is what a reorder is measured against, and it should be identifiable at a glance.

Common mistakes

• Building it in the wrong order. A construction section written before the fabric is chosen will be rewritten.
• Describing the outside. The invisible parts are where interpretation and cost both sit.
• Omitting the base size. Everything below it becomes ambiguous.
• Not stating how each point is measured. The most common source of an unresolvable measurement dispute.
• Leaving tolerances out. Without them, inspection has nothing to pass or fail against.
• Editing in place. Two live versions and no way to tell which is which.
• Treating the first sample as the pack. A garment proves something can be made; it does not record how, or within what range.

How we help build one

Luxudress has manufactured womenswear in Guangzhou since 1995, producing over 100 new styles a month. Most packs we receive are incomplete, and that is a normal starting point rather than a problem.

1. We tell you what is still open, in the order it needs closing.
2. We measure the reference garment and return the numbers, so the chart has a factual basis.
3. We name the measurement methods we are working to, so the chart can be read the same way twice.
4. We flag construction risk before the pattern is cut rather than after the sample.
5. We return the chart we worked to so it can be approved rather than inferred.
6. We hold the approved version, which is what makes your reorder a repeat.

If you are writing your first pack, send the reference and whatever you have noted down and we will tell you what is missing. Product development covers the stage around it, and manufacturing without a tech pack covers the alternative.

Frequently asked questions

How long does it take to write one?

A first pack for a simple style takes an afternoon if you have a reference garment to measure. The time is not in the writing; it is in the decisions. A pack that takes a week is usually one where the fabric and the construction were still being chosen rather than recorded.

What should I write first?

The base size and the measurement chart. Everything else can be developed, but a factory cannot draft a pattern without knowing what body the garment is for and what the key measurements are. Starting with the drawings is the common mistake, because drawings feel more like design work.

What if I have no reference garment to measure?

Use a size chart from a product you know fits your target customer, and say that is what it is. That gives the pattern maker a body standard to work from, which is the thing that is otherwise invented. What does not work is a description of the garment's appearance with no measurements and no reference at all.

Do I need to be able to draw?

You need to be able to make a clear, measured flat drawing, which is a different skill from illustration. Straight lines, correct proportions and labelled seams matter; style and rendering do not. If drawing is genuinely not workable, a measured reference garment plus a written description of the changes is a workable substitute.

Should I use tech pack software?

Use whatever produces a legible, versioned document. Specialist tools help with libraries and grading, and they do not remove the need for the underlying decisions. A numbered PDF with a readable chart is entirely workable and is what many factories prefer to receive.

Who owns the pack I write?

You do, normally, since it describes your product. Where a factory develops the specification on your behalf, agree in writing which parts transfer when the relationship ends — otherwise the document becomes a reason you cannot move production.

Which version is the one that matters?

The version approved at pre-production. Everything before it is development, and everything after it should be measured against it. A reorder is a repeat only if that version still exists and can be identified, which is the practical reason to keep approved versions separately from working drafts.

Conclusion

Writing a tech pack is six passes in a fixed order: identity and base size, flats, measurements with tolerances, construction, materials and trims, then finish and packing. Each pass depends on the one before it, which is why assembling one out of order produces a document that contradicts the garment.

Start with the base size and the chart, state how every point is measured, describe the inside of the garment, and date every issue. Those four habits are most of the difference between a pack a factory can build from and one it has to interpret.