What is the difference between proto, fit and PP samples?

Short answer: Sample names vary between factories, but the stages usually have different purposes. A proto sample is the first interpretation of the design. It checks that the style, construction and proportions are understood, and it may be made in similar rather than final fabric. A fit sample is made to the base size measurements and checked on a body. It is used to correct pattern issues such as rise, leg opening, pouch shape and waistband tension, and there may be more than one fit round. Body measurement definitions such as those in ISO 8559-1 help both sides describe where a change is needed. A pre-production, or PP, sample is made after fit is approved, using the bulk fabric, elastic, trims, labels and packaging, ideally by the production line. It confirms that everything is correct before cutting, and it becomes the reference for bulk. Bulk inspection, often using sampling plans from ISO 2859-1 with an AQL agreed in the contract, then compares production against that approved PP sample and the specification. Skipping stages can work for simple repeat styles, but for a new style, combining proto and fit is more common than skipping the PP sample, which protects bulk.

Proto sample

• First interpretation of the design.
• May use similar fabric.
• Checks style and construction.

Fit sample

• Base size, close to final fabric.
• Checked on a body.
• Corrects pattern and proportions.

PP sample

• Bulk fabric, trims and labels.
• Made like production.
• Reference for bulk and inspection.

A worked example

As an illustration, a brand adapting an existing boxer brief block could combine proto and fit into one round, then approve a PP sample with bulk fabric, labels and packaging before cutting starts.

Size sets

Some brands also request a size set, one piece in each size, to check grading before bulk. This is useful when the range includes very small or large sizes.

Top-of-production samples

Some buyers also ask for top-of-production, or TOP, samples taken from the first pieces off the line. They show whether the line is reproducing the PP sample before most of the order is sewn, and they give an early chance to correct problems while quantities are still small.

Limits

Factories use different names for stages. Agree in writing what each sample stage includes and which materials will be used.

Facts, recommendations and uncertainty

Established: proto checks the idea, fit checks the pattern on a body, and PP confirms bulk materials and making. Recommendation: do not skip the PP sample for a new style. Uncertain: how many fit rounds a particular style will need.

Sources and further reading

• ISO 8559-1:2017 — Size designation of clothes: anthropometric definitions for body measurement
• ISO 2859-1:2026 — Sampling procedures for inspection by attributes (AQL)

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.