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.

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.

What is yarn chicken tolerance?

Yarn chicken is the gamble of whether you will run out of yarn before finishing. Setting a tolerance percentage reduces the total meterage needed, accepting the risk that you might run short. A 0% tolerance is the safest option.

How do I find the meterage of my yarn?

Check the ball band (label) on your yarn. It will list the weight (e.g. 100g) and the meterage (e.g. 200m per 100g). If the ball band shows yards, multiply by 0.914 to convert to metres.

KnitCalcs

Yarn Substitution Calculator — Calculate Yarn Needed When Substituting

Work out how much substitute yarn you need when the original is unavailable, comparing meterage, weight, cost and gauge.

Pattern Yarn

Pattern Meterage

Metres per 100g of pattern yarn

Pattern Total Weight

Total grams required

Pattern Price Per Ball (optional)

For cost comparison

Substitute Yarn

Substitute Meterage

Metres per 100g of substitute

Substitute Ball Size

Weight of one ball or skein in grams

Substitute Price Per Ball (optional)

Cost of one ball or skein

How We Calculate This

This calculator works out how many balls of substitute yarn you need by matching the total meterage of the original pattern requirement, with adjustable safety margins.

The formula

Total metres = Pattern weight (g) x Pattern meterage per gram

Adjusted metres = Total metres x (1 - yarn chicken %)

Substitute balls = Adjusted metres / Metres per substitute ball + Safety margin balls

Frequently Asked Questions

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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.