How do I calculate yarn for Fair Isle colourwork?

Multiply the finished dimensions of the colourwork section to get its area. Divide that area by the number of colours (assuming roughly equal coverage) to get each colour's share, then apply a float waste factor of 10-20%. The exact amount depends on how often colours alternate — a checkerboard uses more yarn than wide stripes.

Why does colourwork use more yarn than plain knitting?

Stranded colourwork carries unused colours across the back of the work as floats. These floats add extra yarn length that does not appear on the right side. The more colours you use and the more frequently they alternate, the greater the float waste. Typically add 10-20% over a plain knitting estimate.

What is colour dominance in stranded knitting?

In two-colour stranded knitting, one colour appears more prominent than the other based on how you hold the yarns. The yarn held below or in your left hand (continental style) travels a slightly longer path and covers more stitch area, making it dominant. Use this for your main motif or foreground colour.

How long can floats be?

Keep floats to a maximum of 5-7 stitches to prevent the fabric from puckering and to maintain elasticity. For longer colour gaps, weave the float yarn through the back of stitches every 4-5 stitches. Long unworked floats also snag when the garment is worn.

Should I buy extra yarn for colourwork?

Yes. Always buy at least one extra ball of each colour. Colourwork yarn estimates are less reliable than plain knitting because float length varies greatly depending on the chart design. It is far better to have extra than to run short mid-project, especially if dye lots matter.

KnitCalcs

Colour Work Yarn Calculator — Yarn Per Colour for Stranded Knitting

Calculate how much yarn you need per colour for Fair Isle, stranded colourwork and other chart-based colour knitting projects.

Chart Width

Total stitches across the colourwork chart

Chart Height

Total rows in the colourwork chart

Number of Colours

Total distinct colours in the chart

Yarn WeightChoose the weight closest to your yarn

Stitch Gauge

Stitches per 10cm from your tension swatch

Row Gauge

Rows per 10cm from your tension swatch

How We Calculate This

This calculator converts your chart dimensions into a physical area, then estimates the yarn needed per colour based on your gauge, yarn weight, and float waste allowance.

Formulae

Chart width (cm) = Chart stitches / Stitch gauge x 10
Chart height (cm) = Chart rows / Row gauge x 10
Yarn per colour = Area x yarn density x (1 / colours) x float multiplier x safety buffer

Float multiplier accounts for yarn used in floats on the wrong side. Safety buffer adds a reserve for tension variation and finishing.

Frequently Asked Questions

Related Calculators

Stripe Sequence Calculator

Calculate yarn needed per colour for striped patterns with custom sequences.

Fair Isle Yarn Calculator

Calculate yarn needed for each colour in a Fair Isle pattern based on percentage.

Intarsia Yarn Calculator

Calculate yarn lengths for each colour block in intarsia colourwork.

Colour Block Calculator

Calculate yarn for large colour block sections in garments.

Gradient Calculator

Calculate yarn quantities for gradient or ombre colour transitions.

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.