Dye Bath Ratio Calculator
A repeatable dye recipe scales everything to the dry weight of the fiber. The dye amount is set by depth of shade, a percentage on weight of fiber; the water amount is set by the liquor ratio, the volume of water per unit of fiber; and auxiliaries like salt or soda ash are also dosed as a percentage of fiber weight. This calculator takes your fiber weight and those three settings and returns the dye weight, the water volume, and the auxiliary weight, so you can mix the same shade at any batch size. It does the proportional math only; the percentages themselves come from your dye manufacturer's instructions, never a guess.
Dye bath formula
dye weight = fiber weight * (depth of shade / 100)
water volume (mL) = fiber weight (g) * liquor ratio
water volume (L) = water volume (mL) / 1,000
auxiliary weight = fiber weight * (auxiliary % / 100)
Water volume assumes 1 gram of water equals 1 milliliter, which holds for water near room temperature. The liquor ratio is the multiplier of water volume to fiber weight (for example 20 means a 20:1 bath).
Using the result
- Always weigh dry fiber before wetting; depth of shade is a percentage of the dry weight.
- Stock dye solutions let you measure tiny dye weights accurately for pale shades.
- A higher liquor ratio promotes level, even dyeing; a lower ratio can give mottled effects.
- Set the auxiliary percentage from your dye's instructions; salt and soda ash levels differ by dye class.
- Follow the manufacturer's safety data sheet for handling, ventilation, and disposal.
Dye bath ratio: frequently asked questions
What is depth of shade?
Depth of shade (DOS) is the weight of dye used as a percentage of the dry weight of the fiber being dyed. A 1 percent depth of shade means the dye weight equals 1 percent of the fiber weight. Pale shades use a fraction of a percent; deep or black shades may use 4 percent or more. It is the standard way dyers scale a recipe to any amount of fiber.
What is the liquor ratio?
The liquor ratio is the ratio of water volume to fiber weight, written like 20:1, meaning 20 units of water per 1 unit of fiber. It controls how freely the fiber moves and how evenly dye distributes. A higher liquor ratio gives more even, level results; a lower ratio can give more variegated effects.
How much dye do I need?
Dye weight equals fiber weight times depth of shade divided by 100. For 100 grams of fiber at a 2 percent depth of shade, you need 2 grams of dye. This calculator does that math and also scales any auxiliaries you enter as a percentage of fiber weight.
Why is salt or auxiliary expressed as a percentage?
Salt, soda ash, and other auxiliaries are dosed relative to fiber weight (a percentage on weight of fiber) so the recipe scales cleanly. Because exact amounts depend on the specific dye chemistry and manufacturer, this calculator keeps the auxiliary percentage as a user-editable input you set from your dye's instructions.
Does this calculator know my specific dye's recipe?
No. Every dye class and brand has its own recommended depth of shade range, salt levels, and fixation steps. This tool does the proportional scaling math from the figures you provide. Always follow your dye manufacturer's instructions and safety data sheet for exact quantities and handling.
Official sources
- U.S. National Institute of Standards and Technology: Office of Weights and Measures (gram, milliliter and liter definitions).
- NIST: National Institute of Standards and Technology (SI unit conversions).
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.