Colorwork Yarn Estimation: Per-Color Math for Tapestry, Mosaic, Fair Isle, C2C, and Graphgan

Per-color yarn for a colorwork chart equals stitches in that color × yards per stitch × a technique-specific multiplier × (1 + buffer), rounded up to whole skeins. The technique-specific multiplier captures what makes colorwork different from solid-color knit or crochet: tapestry uses ~5 yards per 100 stitches because unused colors are carried behind the work, mosaic uses ~4 because they aren’t, and fair isle multiplies your base yards-per-stitch by 1.20 to account for floats. Sum the per-color skeins; that is your shopping list. The Stitchsums tapestry, mosaic, and fair isle calculators run this math from your chart counts and yarn label numbers, with the safety buffers built in.

Tapestry crochet works one row, one row, one row in single crochet with the unused color(s) carried inside the stitches as you go. Because each stitch wraps around the carried strand, every stitch uses a little bit of every color in the row — not just the one you’re working. That makes tapestry yarn-hungry: a worsted tapestry-crochet project typically consumes about 5 yards per 100 stitches, compared with roughly 3–4 yards per 100 for plain single crochet in the same weight. Buffer at 15%: tapestry has more waste from strand management at color changes and ends to weave in. Calibrate from a swatch — the true rate depends on hook, tension, and how loosely you carry. Stitchsums’s tapestry yarn calculator takes per-color stitch counts plus your calibration and returns per-color yards and skeins to buy, with both totals.

Mosaic crochet works in two-row pairs: a background row in color A, then a design row in color B made largely of slip stitches that catch the chart from below. The unused color is not carried — it waits at the edge of the work until its next row. Because there are no carried strands inside the stitches, mosaic uses less yarn per stitch than tapestry. A worsted mosaic project typically lands around 4 yards per 100 stitches rather than tapestry’s 5. Buffer at 10%: slip-stitch rows are short and tidy, with less waste to absorb. Mosaic projects almost always use 2–4 colors — beyond that the chart usually wants revisiting. Stitchsums’s mosaic yarn calculator applies these defaults but lets you override both numbers if your swatch tells you otherwise.

Fair isle knitting (more accurately, stranded colorwork) works two colors per round with the unused color floating across the back of the fabric between color changes. Those floats are pulled to a consistent tension as you knit, which adds a measurable amount of yarn beyond the stitches themselves. The standard adjustment is to multiply your base yards-per-stitch by 1.20 — in other words, fair isle uses about 20% more yarn per stitch than the same gauge worked solid. Tight floats can run as low as 1.15; long floats (more than 5 stitches between color changes) can push as high as 1.30. Pair the float adjustment with a 10% project buffer for swatching and finishing. Stitchsums’s fair isle yarn calculator takes per-color stitch percentages (which must sum to 100), the project total stitches, your yards-per-stitch, and your yards-per-ball, then returns per-color yards and whole balls.

Corner-to-corner (c2c) and graphgan (single-crochet pixel) projects share a common trait: the chart cell is the unit, and the per-color yarn estimate starts with counting cells. For c2c, each chart cell becomes a tile worked in three or six stitches plus joining chains — multiply per-color cell counts by your stitches-per-tile to get per-color stitch counts, then apply the same yards-per-stitch math as a solid-color project (no carry adjustment; c2c does not carry between tiles). For graphgan, each cell is exactly one single crochet, so the per-color stitch count is the per-color cell count. Stitchsums’s c2c diagonal stitch count and graphgan stitch count calculators handle the chart-totals side; combine them with the yardage substitution calculator for per-color yardage when each color is a solid block.

A stripe sequence project repeats a pattern like 4 rows navy, 2 rows white, 6 rows navy, 2 rows white indefinitely — meaning many physical stripes belong to the same color. Per-color yarn for stripes is not just the sum of stripe stitch counts; it is the sum of stitch counts grouped by color name. The Stitchsums stripe sequence yarn calculator does exactly this: you enter each stripe as its own band with name, row count, and stitches-per-row, and the calculator aggregates across the repeating sequence to give you per-color totals. No carry adjustment is applied because stripe colors are joined and dropped at row boundaries, not carried inside the fabric.

Suppose your chart for a tapestry crochet bag is 100 stitches wide by 120 rows tall, with three colors: 6,000 stitches of cream, 4,000 of rust, 2,000 of navy. Total 12,000 stitches. At 5 yards per 100 stitches (worsted tapestry default), raw yards are 300 (cream), 200 (rust), 100 (navy). Apply the 15% buffer: 345 (cream), 230 (rust), 115 (navy). If your yarn comes in 200-yard skeins, the per-color skein counts round up to 2 (cream), 2 (rust), 1 (navy) — 5 skeins total, not 4. That is the load-bearing insight of per-color rounding: dividing the project total (690 yards / 200 = 3.45, rounded up to 4 skeins) understates what you need to buy by an entire skein because you cannot split a skein across colors. Run this through the tapestry calculator with your own numbers to see the same result.

A mosaic throw chart 150 stitches wide by 200 rows tall is 30,000 stitches. Three colors with stitch counts 14,000, 10,000, and 6,000. At 4 yards per 100 stitches (worsted mosaic default), raw yards are 560, 400, 240. Apply the 10% buffer: 616, 440, 264 — round per-color: 616, 440, 264. With 220-yard skeins, per-color skein counts round up to 3, 2, 2 — 7 skeins total. Notice mosaic’s lower per-stitch yardage (4 vs tapestry’s 5) makes a meaningful difference at throw scale: at tapestry rates the same chart would consume about 1,400 yards before buffer instead of the 1,200 here. The mosaic calculator exposes the calibration and buffer as inputs so you can dial them after measuring your own swatch.