The chart shows the relationship between micronaire, fiber fineness, maturity ratio, and theoretical fiber diameter.

Fiber cross-section is assumed to be circular, which makes the fiber diameter lines on the graph approximate. Curves for micronaire level are empirical and therefore contain experimental error.

Fiber fineness (fiber linear density) is expressed in micrograms/in. or in millitex (µg/m). The practical range of fineness for U.S. Upland cotton is about 125-225 millitex.

Micronaire is expressed in dimensionless micronaire units. The practical micronaire range for U.S. Upland cotton is 2.0 – 6.0.

Maturity ratio is a measure of the relative amount of cellulose in the fiber cross-section. Values are dimensionless numbers in the 0.7 – 1.2 range.