Composites
Prepreg is specified by weight and performs by volume. With carbon at 1.79 and epoxy at 1.24, those are different numbers.
— g/m²
Fibre plus resin as the roll is supplied
Assumes no void content and no resin bleed. A real autoclave cycle bleeds resin and consolidates, so cured ply thickness comes out below this and fibre volume fraction above it — which is usually the intention. Aerospace laminates must be qualified by coupon testing; this is layup planning, not substantiation.
Carbon Prepreg Resin Content & Ply Thickness Calculator — free, with the formula and a worked example, at Textile School.