How to read a clothing fiber content label: the 5 percent rule and the 19 micron cashmere test

A clothing fiber content label lists each fiber by its generic name and its percentage by weight, in descending order, and groups fibers under 5 percent as "other fiber." Federal rules from the Federal Trade Commission set those lines, and a separate rule sets the test for the word cashmere.

Most shoppers read the first line of the tag and stop. The rest of it, the order, the small print and the origin, is where the law does its work.

What the label must show

The FTC says textile labels must identify fiber content and country of origin, and the maker or dealer by company name or Registered Identification Number. The rules cover most clothing except hats and shoes, plus bedding, towels and curtains. Wool products include any product containing any amount of wool, including recycled wool.

The fiber line comes from 16 CFR 303.16, which requires "the generic names and percentages by weight of the constituent fibers present in the textile fiber product." Fibers are listed in descending order by weight. Generic names are required for both natural and man-made fibers, so a tag says cotton or polyester in the rule's terms.

The 5 percent rule

Fibers making up 5 percent or more of the weight are named with their percentage. Fibers under 5 percent are grouped as "other fiber" or "other fibers," and that designation goes last. The practical effect is that a tag can legally compress a small share of an expensive or unusual fiber into a single bucket.

That is worth knowing when a brand's product page talks about silk or cashmere "blended in." If the tag shows 3 percent, it may appear only as "other fibers." Ask for the number before you pay for the word.

Trim, and what it hides

Not every part of a garment counts. The FTC's guide excludes various trim, such as collars, cuffs, braiding and labels, from fiber content labeling. Decorative trim and designs are exempt if they cover 15 percent or less of the surface area. Beyond that, the fiber must be disclosed.

So a coat with decorative trim can have a tag that says nothing about the trim. The body fabric is what the line describes.

Cashmere has its own legal test

Cashmere is the one fiber with a statutory fineness test in the Wool Products Labeling Act rules. Under 16 CFR 300.19(a)(1), the term "cashmere" may be used for such fiber content only if the fiber consists of the fine, dehaired undercoat fibers produced by a cashmere goat, if the average diameter does not exceed 19 microns, and if no more than 3 percent by weight of the cashmere fibers have average diameters that exceed 30 microns. The rule text carries a June 4, 2014 Federal Register source note.

Two points follow. First, a sweater labeled cashmere has cleared a fineness bar, which is a floor, not a grade. Our explainer on what is cashmere covers the fiber in more depth. Second, in a blend the cashmere share is named like any other fiber, so check the percentage, not just the word.

A worked example

Say a sweater tag reads 80 percent wool, 15 percent nylon and 5 percent cashmere. That is three named fibers, listed heaviest first, and the cashmere share sits right at the 5 percent line where it must be named. If the cashmere were 4 percent, the tag could fold it into "other fiber" and still comply. Either way the percentages should add up to 100, which is a quick check you can run at the rack in seconds.

Origin and the RN number

The tag also names where the item was made. Imported products must identify the country where they were processed or manufactured, not just a region such as the EU. The maker line can be a company name or an RN, a number issued by the FTC to US firms that handle textile, wool or fur products. The FTC says an RN is not required to do business in the US, and it does not issue RNs to businesses outside the country.

What happens when it is wrong

The FTC treats violations of the Textile, Wool and Fur Acts as unfair methods of competition and as unfair or deceptive practices. Violators of an administrative order face civil penalties of up to $53,088 per violation, and each instance of mislabeling is a separate violation. Businesses without a prior order can face civil penalties, injunctions and consumer redress in federal court, particularly for knowing violations. Improperly labeled imports can be held by Customs and may face liquidated damages.

This piece cites the regulations themselves, not a company or an official, because no named person has commented on these rules in a way that adds to the text.

How to use this at the rack

Read the first fiber line for the main material. Add up the named percentages: if they fall short of 100, the remainder is under the 5 percent grouping or listed as "other fibers." Check the origin line, which is separate from the brand's marketing story. For a wool item, see whether the care and fiber lines agree with how it should be washed; our guide to how to wash wool covers the cleaning side.

Our take

The label is a legal minimum, reliable on what is in the garment and silent on quality. Trust the percentages, discount the adjectives, and treat "other fibers" as a prompt to ask a question. For cashmere, the 19 micron line is a real test, but it only proves the fiber qualifies, not that the sweater is good.