How we count natural content

Fiber composition is the foundation

We weight every fiber in a garment by its type. Natural fibers (cotton, linen, hemp, wool, and silk) count in full at 100%, and they count the same whether or not they're organic, because organic is a certification, not a fiber, so it never changes the number. Wood-based regenerated cellulosics count in part, graded by how they're made: lyocell 70%, modal 55%, viscose and cupro 45%, acetate 30%. Synthetics like polyester and nylon count as zero. Certifications like GOTS and OCS are verified and filterable, but they don't move the natural content figure, which reflects fiber alone.

A garment's base score is the weighted average of its declared fiber percentages.

Certifications, checked separately

Independent third-party certifications (GOTS, OEKO-TEX, OCS, GRS, RWS) confirm what the label claims. A certification appears on a product only when the brand's claim survives our verification gating, and where the issuer runs a public certificate register we go further: we match the brand's certificate number against the register itself, and only that registry match is labelled a verified certificate. Certifications are filterable, but they never change the natural content figure: the percentage is computed from fiber composition alone, so it stays a pure measure of what a garment is made of.

The MaterialFilter Verification Method

The MaterialFilter Verification Method is the pipeline behind every number on this site: fiber composition is extracted from each brand's own published product data, products are tagged across a 54-material shopper taxonomy with material and certification tags held to a confidence floor before anything is displayed, and certification claims are checked against issuers' public registers wherever one exists. The same pipeline computes the aggregate catalogue statistics we publish nightly.

See the numbers for yourself: the aggregate catalogue statistics are recomputed nightly and licensed CC BY 4.0.