Tie-Dye Calculator (Dye, Soda Ash, Water & Bottles)

How it works

dye (g) = fabric weight × % on weight of fabric (pastel 0.5, medium 2, deep 4, black 8) × coverage · solution ≈ 0.6 mL per g of fabric · soda ash = 250 g (1 cup) per 4 L; soak ≈ 0.6 L per 100 g fabric · 1 level tsp Procion ≈ 2.5 g

Fibre-reactive dyes bond chemically to cotton in an alkaline bath, so the depth of colour depends on how much dye is available per gram of fibre — dyers call it percentage on weight of fabric — rather than on how strong the bottle looks, and soda ash provides the alkalinity that makes the bond happen. Scaling a batch therefore starts from the total dry weight of the garments: dye follows the shade percentage, solution volume follows how wet a garment must be to saturate, and the soda-ash soak follows the water needed to submerge the lot at a fixed cup-per-gallon strength. Because the dye starts reacting with water as soon as it is mixed, the solutions are made fresh, and the long warm cure is what lets the reaction finish before the excess is washed away.

Worked example

Ten adult T-shirts (1.8 kg) in three bright colours at 90% coverage need 32 g of dye in total, about 11 g per colour dissolved in 324 mL each (≈ 3.2 tsp per cup), roughly 97 mL of solution per shirt. Soak them in 11 L of water with 690 g (2¾ cups) of soda ash, bag for 12–24 hours and wash out — about five extra machine loads.

Frequently asked questions