400 grams of yarn. How much dye?
Weight-of-fiber times depth of shade — the convention every dye house and careful hand-dyer shares — plus the stock-solution pour, because at these weights a syringe beats a scale. Everything stays in your browser.
The bath
The numbers here are yours to check. This page does arithmetic on what you type — it cannot see your recipe, your equipment or your batch.
Want it to remember?
In MadeKeeper the dye jars are inventory by the gram, each bath's recipe lives with its colorway, and a repeat skein consumes exactly what the first one did — records at the pot, kept for you. See for yarn dyers or poke around the live demo. $19/mo for the whole back office, kept for as long as you stay. The shop stays free for cost a piece and one fair — no product cap. The tax packet, Etsy and Square, and more fairs are the $19.
WOF math, the professional convention
Dye math is the difference between a repeatable colorway and a happy accident. The math below is the same math the calculator runs — the convention named, the aesthetic calls left where they belong.
What is depth of shade?
Dye as a percentage of the fiber's dry weight — the convention that makes a color repeatable. One percent DOS on 400 grams of yarn is 4 grams of dye powder, whatever the dye. Half a percent is a pale wash, one percent a solid mid, three percent saturated — and the exact hue at each depth is your dye's personality, which is what sample skeins are for.
Why dye from a stock solution?
Because 0.4 grams of powder is a guess on most scales and 40 milliliters of stock is not. Dissolve dye at a known strength — one gram per hundred milliliters is the bench-standard 1% stock — and every future measurement is a pour instead of a weigh. The stock also levels better: pre-dissolved dye strikes more evenly than powder chasing itself around the pot.
Does this work for every kind of dye?
The WOF arithmetic is universal — acid dyes on wool, fiber-reactive on cotton, all measure by weight of fiber. What differs is everything around the math: the assists (acid vs soda ash), temperatures, times, and each brand's real strength per gram. Your dye supplier's instructions own that part; this page owns the arithmetic.
How do I repeat a color I loved?
Records — which is the honest secret of every dyer whose colorways match across years. The formula is only three numbers: the fiber weight, the DOS, and which dyes in what proportions. Write them at the pot, not after. A colorway you can repeat is a product; one you can't is a story.