How many sample rounds are normal for a new underwear style?

Short answer: There is no fixed number of sample rounds, because it depends on how new the style is, how clear the brief is and how quickly comments are closed. A repeat of an existing block in a new colour may need only a PP sample. A small change to an existing style, such as a different inseam or waistband, often needs one fit round plus a PP sample. A completely new style, new fabric and new fit may need two or three fit rounds before PP. Rounds multiply when comments are vague, when the brand changes the design between rounds, when samples are reviewed on different bodies each time, or when fabric is changed after fit approval. To keep rounds down, start from a clear tech pack with a measurement chart, use one fit model or a consistent fit process, and give numbered comments with measurements rather than impressions. Body measurement terms from ISO 8559-1 help describe where a change is needed. Check shrinkage before final fit approval, for example with ISO 5077, because a fabric that shrinks can make an approved fit wrong after washing. If rounds keep repeating the same comment, ask the factory to explain why the change is not being made.

What drives the number of rounds

• How new the style and fabric are.
• Clarity of the tech pack.
• Design changes between rounds.
• Consistency of fit reviews.

Ways to reduce rounds

• Start from a proven block.
• Use numbered, measured comments.
• Keep one fit process.
• Freeze design before fit.

Warning signs

• The same comment repeating.
• New problems appearing each round.
• Samples arriving without measurement sheets.

A worked example

As an illustration, a brand could freeze the design after the proto, review fit on the same person each round, and send comments such as raise the rise by one centimetre at centre back, rather than feels low.

Planning time

Each round adds the time to make, ship and review the sample. Plan the calendar with one more round than you expect.

Combining stages

When time is short, some stages can be combined, for example a proto and first fit in one round, or a final fit made in bulk fabric so it can serve as the PP sample. This saves time only if the brief is clear and materials are already decided; otherwise it can add rounds later.

Limits

Some fabrics, such as very stretchy or very fine knits, need more rounds because small pattern changes behave differently in them.

Facts, recommendations and uncertainty

Established: the number of rounds depends on style novelty, clarity and stability of the brief. Recommendation: freeze the design early and send measured, numbered comments. Uncertain: how a new fabric will behave until it is sampled and washed.

Sources and further reading

• ISO 8559-1:2017 — Size designation of clothes: anthropometric definitions for body measurement
• ISO 5077:2007 — Determination of dimensional change in washing and drying

Standards and regulations are referenced by their published scope. Test parameters, cycles and pass levels should be agreed with your laboratory for the specific product; legal requirements should be confirmed for each destination market.