What is depth of shade (DOS)?

Depth of shade is the percentage of dye weight relative to the weight of fibre being dyed. For acid dyes, 0.5% gives a pale shade, 2% gives a medium shade, and 4–6% gives a dark shade. Natural dyes use much higher percentages because the pigments are less concentrated.

Why do I need a mordant for natural dyes?

Mordants (typically alum at 15% weight of fibre) help natural dye molecules bond permanently to the yarn. Without a mordant, most natural dyes will wash out. Mordant the yarn in a separate bath before dyeing for best results. Alum is the safest and most common mordant.

How much water do I need for dyeing?

The standard ratio is 30:1 water to fibre by weight — so 30ml of water per gram of yarn. This gives enough water for the yarn to move freely in the dye bath, ensuring even colour. For immersion dyeing, the yarn should float loosely in the pot.

Do I need to pre-soak the yarn?

Yes, always. Soak the yarn in warm water for at least 30 minutes before dyeing. This opens the fibre structure, removes any spinning oils and ensures even dye uptake. Gently squeeze out excess water before placing yarn in the dye bath.

KnitCalcs

Yarn Dyeing Calculator

Calculate dye powder, water and mordant amounts for hand-dyeing yarn.

Dry Yarn Weight

Weight of dry yarn to be dyed

Dye Type

Choose the type of dye

Depth of Shade

How dark or saturated you want the colour

How We Calculate This

This calculator works out dye, water and mordant amounts based on your yarn weight, chosen dye type and desired depth of shade.

Formulas

Dye amount = Yarn weight × (DOS % ÷ 100)

Water volume = Yarn weight × Water ratio (default 30:1)

Acid (for acid dyes) = Yarn weight × 4%

Mordant (for natural dyes) = Yarn weight × 15%

Typical DOS percentages

Acid dyes: 0.5% pale, 2% medium, 4% dark, 6% very dark
Fibre reactive: 0.5% pale, 2% medium, 4% dark, 8% very dark
Natural dyes: 25% pale, 50% medium, 100% dark, 150% very dark

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Last updated: March 2026

All calculations are estimates based on standard yarn weights and gauge. Results may vary with individual tension, yarn brand, and needle size.