Dye Bath Calculator

A dye bath is the water-and-dye solution a textile is immersed in during dyeing, and getting its proportions right is what makes a dye lot repeatable rather than a guess. This calculator works from Fabric Weight (dry) -- the standard reference point in textile dyeing, since all the other quantities are expressed as a percentage of it. Shade Depth is the dye's weight as a percentage of the fabric's weight (technically "percent on weight of fiber," or %owf): a pale tint sits around 0.5%, a medium shade around 2%, and a dark, saturated color can run 5% or higher, and Dye Weight scales directly with it. Liquor Ratio is the ratio of water to fabric by weight -- a liquor ratio of 20 means 20 mL of water for every 1 g of dry fabric -- and it drives Water Volume, converted here to both liters and US gallons for convenience at different batch sizes.

A tighter liquor ratio concentrates the dye bath and can produce a deeper shade with less dye, while a looser ratio (more water relative to fabric) gives the fabric more room to move for even coverage but dilutes the dye, which is why commercial recipes specify liquor ratio as carefully as shade depth. Auxiliary Weight covers the leveling agents, wetting agents, and other dye-assist chemicals dosed as a percentage of fabric weight, independent of both shade depth and liquor ratio. Salt (est.) estimates the sodium chloride commonly added to exhaust reactive dyes onto cellulose fibers like cotton -- salt does not react with the dye itself, it drives more of the dissolved dye out of the water and onto the fiber, and the estimate here scales up with target shade depth since darker shades need more dye driven onto the fiber. Exact dye, salt, and auxiliary dosing still varies significantly by dye class (reactive, acid, disperse) and fiber type, so treat these figures as a recipe starting point to confirm against your specific dye manufacturer's technical data sheet.