Moisture Regain Calculator
Regain is water as a share of dry weight: a sample of 110 g that dries to 100 g has a regain of 10 % and a moisture content of 9.09 %.
Cotton 8.5 %, wool 16 %, polyester 0.4 %, viscose 13 %.
10 %
- Moisture regain R = (W − D)/D
- 10 %
- Moisture content M = (W − D)/W
- 9.09091 %
- Commercial weight at 8.5 % regain
- 108.5
Step-by-step solution
- R = (W − D)/D, M = (W − D)/W
- R = M/(1 − M), M = R/(1 + R)
- R = 10 %, M = 9.09091 %
Moisture Regain Formula
R = (W − D)/D, M = (W − D)/W
W conditioned weight, D oven-dry weight; R = M/(1 − M)
Worked Example
A sample weighing 110 g conditioned and 100 g oven-dry:
- R = (W − D)/D, M = (W − D)/W
- R = M/(1 − M), M = R/(1 + R)
- R = 10 %, M = 9.09091 %
Moisture content M = (W − D)/W: 9.09091 % · Commercial weight at 8.5 % regain: 108.5
Standard atmosphere and commercial regain
Regain depends on the humidity and temperature at which the fibre is conditioned, so tests use the standard atmosphere of 65 % RH and 20 °C (ISO 139). Hydrophilic fibres such as wool (about 16 %) and viscose (about 13 %) hold far more water than polyester (about 0.4 %). Trade invoices use an agreed commercial regain, so a lot is paid for at its oven-dry weight plus that regain, not at its actual weight on the day.
More Textile Testing Calculators
-
Yarn Evenness Calculator
CV = s/x̄ × 100, CVlim = 100/√n, I = CV/CVlim
n fibres in the cross-section = yarn tex ÷ fibre tex
Example: Eight cut-length masses of a 20 tex yarn spun from 1.5 dtex fibre: Coefficient of variation CV = 3.62531 %.
-
Fabric Shrinkage Calculator
s = (L₀ − L₁) ÷ L₀ × 100
area shrinkage = 1 − (1 − sₗ)(1 − s_w)
Example: A 50 × 50 cm mark that measures 48.5 × 49 cm after washing: Lengthwise (warp) shrinkage = 3 %.
Frequently asked questions
Why is regain always higher than moisture content?
Both use the same water mass, but regain divides by the dry weight, which is smaller than the wet weight.
What is commercial weight?
The invoice weight at the agreed standard regain: dry weight × (1 + standard regain). For cotton at 8.5 %, 100 kg dry is billed as 108.5 kg.
Sources
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Moisture Regain Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/moisture-regain-calculator/
IEEE
Scientific Converters, "Moisture Regain Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/moisture-regain-calculator/