How do I calculate yarn for Fair Isle colourwork?

Count the total stitches in the chart (width x height). Each stockinette stitch uses roughly three times its own width in yarn, so yarn per stitch (m) is about 3 x (10 / your stitch gauge) / 100. Multiply by the stitch count for the plain total, divide by the number of colours for each colour's rough share, then add 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.

Colour Work Yarn Calculator — Free Stranded Knitting Tool

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 counts the total stitches in your chart, then estimates the yarn needed per colour using the established “one knit stitch consumes about three times its stitch width in yarn” rule, scaled by your gauge, float waste allowance and safety buffer.

Formulae

Chart width (cm) = Chart stitches / Stitch gauge x 10
Chart height (cm) = Chart rows / Row gauge x 10
Stitch width (cm) = 10 / Stitch gauge
Yarn per stitch (m) = 3 x Stitch width / 100
Plain yarn (m) = Chart width x Chart height x Yarn per stitch
Yarn per colour = Plain yarn x (1 / colours) x float multiplier x safety buffer

The 3x-stitch-width rule is the accepted rule of thumb for stockinette yarn consumption (real values run roughly 3.0–3.5x; this calculator uses the conservative 3.0x). Float multiplier accounts for yarn carried across the back on the wrong side. Safety buffer adds a reserve for tension variation and finishing. The per-colour figure is a rough average — in practice the background colour uses far more yarn than contrast colours.

Frequently Asked Questions

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.

Colour Work Yarn Calculator — Yarn Per Colour for Stranded Knitting

How We Calculate This

Formulae

Frequently Asked Questions

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