Free knitting & crochet tool

Yarn Substitution Calculator

Switching yarns? Match the total length in your pattern and find out how many balls or cones of your new yarn to buy.

Your yarn details

Use the same unit throughout.

Pattern yarn

The yarn specified in your pattern.

Balls or cones needed

Length per ball or cone (m)

Substitute yarn

The yarn you would like to use instead.

Length per ball or cone (m)

Extra allowance

Optional gauge check

Enter stitches over the same measurement, usually 10 cm or 4 in.

Pattern gauge

Your swatch gauge

Your result will appear here

Enter the length printed on each yarn label. We calculate by length—not weight—because ball and cone sizes vary.

How to substitute yarn successfully

Match the gauge

Choose a yarn that can comfortably achieve the pattern gauge. Needle size alone is not a guarantee.

Compare the fibre

Wool, cotton, silk and alpaca differ in elasticity, drape, warmth and care requirements.

Swatch and wash

Measure after washing and drying as you will treat the finished piece. Adjust needle size if needed.

Important note

This calculator estimates quantity from length. Texture, fibre, stitch pattern, gauge changes and personal tension can affect actual usage. For garments or discontinued yarns, buying one additional ball may be sensible.