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Yarn Quality Parameters: CV%, CSP, IPI and RKM

27 July 2026 by

Yarn quality reports are full of abbreviations. Here is what the main ones mean, so you can read a spec with confidence.

CV% (evenness)

Coefficient of variation of mass — how uniform the yarn is along its length. Lower is better. See yarn evenness (CV%).

CSP (strength)

Count Strength Product — count (Ne) × lea strength (lbs), a count-independent strength indicator. Higher is stronger. Use the CSP calculator.

IPI (imperfections)

Imperfections Index — thin places, thick places and neps per unit length. Lower is cleaner.

RKM (tenacity)

Breaking length in kilometres (grams per tex, roughly) — a measure of yarn tenacity. Higher is stronger.

Reading them together

For critical fabric, ask for CV%, CSP/RKM and IPI alongside the count — and, crucially, consistency batch to batch. That is what our quality standards are built on.

Want documented, consistent yarn quality? Tell us your parameters.

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See the glossary for every term, and our yarn guides.

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