Yarn is bought and sold by weight — and weight changes with moisture. Understanding regain helps you compare quotes fairly and avoid weight surprises.
What is moisture regain?
Textile fibres absorb moisture from the air. Moisture regain is the weight of water in a fibre expressed as a percentage of its oven-dry weight. Because it shifts weight, the trade uses agreed standard regains.
Standard regain by fibre
| Fibre | Standard regain |
|---|---|
| Cotton | ~8.5% |
| Viscose | ~11% |
| Polyester | ~0.4% |
| Wool | ~13.6% |
Why it matters commercially
Yarn weighed in very dry or very humid conditions weighs less or more than the same yarn at standard regain. Reputable supply quotes and conditions yarn to standard, so a kilogram is a fair kilogram. When you size an order, remember conditioned weight is the reference.
Conditioning
Yarn is often allowed to condition (reach equilibrium with standard atmosphere) before weighing and dispatch. It also protects yarn from static and breakage — see our guide on storing yarn.
We supply yarn weighed fairly and consistently, mill-direct across India.
More in our yarn guides and glossary.