Calculator
Fair Isle Yarn Calculator
Stranded colorwork uses more yarn than plain knitting — the strands carried behind the work add 15–30% per color. Tell us your project totals and per-color percentages and we'll give you yards and ball counts per color.
Calculator
How this works
For each color, we compute:
yards = total stitches × (color % ÷ 100) × yards per stitch × float adjustment.
Then we round up to whole balls — you can't buy a fraction of a ball, and you don't want
to run out at row 412 of 413. Working in crochet instead? The same per-color math powers
our tapestry crochet yarn calculator and
mosaic crochet yarn calculator.
What is float adjustment?
Stranded knitting (Fair Isle, Scandinavian, Latvian) carries the non-working color behind the working color until it's needed again. Those strands — "floats" — are extra yarn that doesn't appear in the stitch count. The longer the floats, the more extra yarn:
- 1.15 — short floats (2–3 stitches), typical Fair Isle motifs.
- 1.20 — typical, balanced colorwork. The default in this calculator.
- 1.25–1.30 — long floats (5+ stitches), bold geometric motifs, or weaving-in-as-you-go techniques that double the carried yarn.
When in doubt, overestimate. Half a leftover ball is cheaper than a late-night yarn run with a 90% finished sweater.
Where do per-color percentages come from?
Two options:
- Chart analysis. Count cells per color in your chart, divide each by total cells, multiply by 100. Most chart software (including the MathStitch editor) gives you these numbers automatically.
- Estimation. If you're working from a swatch, eyeball the rough balance — "about 60% main color, 30% contrast, 10% accent." The calculator's 0.5% sum-to-100 tolerance forgives small rounding.
Yards per stitch — how do I figure this out?
Yarn use per stitch depends on yarn weight and your gauge. Rough starting points:
- Lace / fingering at 28+ sts/4": ~0.014 yards per stitch
- Sport / DK at 22–26 sts/4": ~0.018 yards per stitch
- Worsted at 18–20 sts/4": ~0.022 yards per stitch
- Bulky at 12–16 sts/4": ~0.030 yards per stitch
For accuracy, measure your swatch: knit a 4-inch square in stockinette, measure how much yarn it took (unravel and measure, or weigh and compute), then divide by the total stitch count.
Tips for accurate estimates
- Use the yards per ball from your yarn's label — substitutions can shift this 20%+.
- Round float adjustment up if you're a tight stranded knitter — you pull more yarn behind.
- Add one extra ball of the main color for finishing (seaming, edgings, repairs).
- If colorwork is only part of the project (e.g., a yoke), compute only those stitches here, and add solid-color yardage separately.
- When two colors are close in percentage, consider buying one extra ball of each — running short on either stops the whole project.