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
Substitute Yarn
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
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.
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.
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.
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.
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Yarn Meterage Calculator
Calculate total metres of yarn needed from weight and meterage per ball.
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Calculate adjustments when substituting one yarn weight for another in a pattern.
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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.