Conditioned (Commercial) Weight Calculator

Turn dry weight into the invoiced commercial weight using the fibre’s commercial moisture regain.

Formula

Commercial weight = dry weight × (1 + R). R = commercial (legal) moisture regain. For a blend, R is the weighted average of the fibre regains by their proportions. Commercial regains: Polyester 0.4% · Nylon 4.5% · Cotton 8.5% · Viscose 12% · Wool 16.5%.

Worked example

100 kg dry cotton → 100 × (1 + 0.085) = 108.5 kg commercial weight. 100 kg dry polyester → 100 × (1 + 0.004) = 100.4 kg. Blend example — 65% polyester / 35% cotton: weighted R = 0.65 × 0.004 + 0.35 × 0.085 = 0.032; 100 kg dry yarn → 103.24 kg commercial weight.

Frequently asked questions

What is commercial weight?

Commercial (conditioned) weight is the contractual, invoiced weight found by adding a fibre’s legal/commercial moisture regain (R) to its bone-dry mass. Formula: commercial = dry × (1 + R). Because moisture varies with air conditions, this standard weight is used instead of a raw weigh-in.

What is the moisture regain of polyester?

Polyester’s commercial moisture regain is 0.4%. It is so low that dry and commercial weight are almost identical: 100 kg dry polyester = 100 × 1.004 = 100.4 kg commercial. For comparison, nylon is 4.5%, cotton 8.5%, viscose 12% and wool 16.5%.

How do I find the invoice weight of a blended yarn?

First compute the weighted-average R from the fibre proportions, then apply commercial = dry × (1 + R). Example: for 65% polyester / 35% cotton, R = 0.65 × 0.004 + 0.35 × 0.085 = 0.032; 100 kg dry yarn → 103.24 kg commercial weight.

What is the difference between dry weight and actual weight?

Dry (bone-dry) weight is the fibre mass with all moisture removed; actual weight is the real, moist weigh-in at delivery. From actual to commercial weight: commercial = actual × (1 + R_commercial) ÷ (1 + R_actual).