Elastane (Spandex)

Elastane (EU), spandex (US), and Lycra (brand) are one fiber: a segmented polyurethane that stretches 5–8× and snaps back. It rarely appears alone — it hides as 2–10% of “cotton” tees, jeans, socks, and nearly everything fitted.

That small share is decisive at end-of-life: even a few percent of elastane keeps a garment out of cotton recycling and composting, and heat steadily degrades the fiber until waistbands crumble.

Elastane scores 100/100. “95% cotton, 5% elastane” scores 5/100 — low, but not zero, and the breakdown always shows the elastane rather than rounding it away.

The same weight applies everywhere: a product's score is the percentage-weighted plastic share of its listed fiber composition, and every weight is public.