What is the most important factor when substituting yarn?

Gauge is the most important factor. The substitute yarn must knit to the same gauge as the original on the same or similar needle size. Matching the weight category (DK, aran, etc.) is a starting point, but always swatch with the substitute yarn. Two DK yarns can have very different gauges depending on fibre content, twist, and ply structure.

Should I match total metres or total grams when substituting?

Match total metres (yardage), not total grams. Different fibres have different densities: cotton is heavier than wool per unit length, and silk is heavier than acrylic. If you match grams instead of metres, you could end up with far too little or too much yarn.

How do I find the meterage of my yarn?

Check the ball band (label) on your yarn. It will list the weight (e.g. 50g or 100g) and the meterage (e.g. 115m or 210m). If the ball band shows yards instead of metres, multiply by 0.914 to convert to metres. If the ball band is missing, you can weigh a measured length of yarn and calculate from there.

Do I need to adjust the pattern when substituting yarn?

If your gauge matches exactly, you should not need to adjust the pattern. However, if the substitute yarn has a different stitch-to-row ratio (e.g. cotton tends to have fewer rows per 10cm than wool at the same stitch gauge), you may need to adjust the number of rows in the pattern. Drape and fabric hand may also differ between fibres.

KnitCalcs

Yarn Substitution Calculator — Match Yardage When Swapping Yarns

Calculate how many balls of a substitute yarn you need when the original is unavailable or you want to use a different yarn.

Original Yarn

Number of Balls (original)

Balls required by the pattern

Metres Per Ball (original)

Check the ball band

Weight Per Ball (original)

Substitute Yarn

Metres Per Ball (substitute)

Check the substitute ball band

Weight Per Ball (substitute)

Price Per Ball (optional)

Enter price for a cost estimate

How We Calculate This

This calculator works out how many balls of the substitute yarn you need by matching the total meterage of the original yarn requirement.

The formula

Total metres needed = Original balls x Metres per original ball

Substitute balls = Total metres needed / Metres per substitute ball (rounded up)

We always round up to whole balls since you cannot buy partial balls. This means you may have some leftover yarn from the last ball, which the calculator shows.

Frequently Asked Questions

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Estimate centre-pull ball dimensions and yardage from skein specifications.

Fibre Content Calculator

Calculate blended fibre percentages when combining multiple yarns.

Yarn Twist Calculator

Calculate twists per inch and twist angle for plied yarns.

Last updated: February 2026

All calculations are estimates based on standard yarn weights and gauge. Results may vary with individual tension, yarn brand, and needle size.