Testing
One-way transport carries half the weight. A fabric that only absorbs is holding sweat against the skin, not managing it.
— index
Zero to one, weighted toward one-way transport
The published method grades each measured value into one of five bands and then blends the grades; this tool interpolates linearly between a declared pair of anchors instead, which is smoother, better for comparing two fabrics inside the same band, and will not reproduce a laboratory report exactly at a band boundary. Where a certificate is being matched, set the anchors to the band edges of the grade in question and read the result as an interpolation within it. One-way transport is the index most sensitive to test conditions and the one most often misread: it is a difference between the two faces, so a fabric can post a high value by being poor on the top face rather than good on the bottom, and a large positive OWTC with a low absorption index usually means exactly that. Nothing measured here is comfort. OMMC describes what a fabric does with a fixed dose of liquid on a bench at fixed humidity, and the wearer experience depends on evaporation into moving air, on garment fit and on where the fabric touches at all - which is why two fabrics with the same OMMC can feel entirely different in wear.
Overall Moisture Management Capability from MMT Indices — free, with the formula and a worked example, at Textile School.