How to Substitute Yarn in a Crochet Pattern

The yarn used in a pattern might be discontinued, unavailable where you live or simply not your favorite color. Substituting yarn is completely normal — you just need to compare a few details so your project turns out the right size.

Step 1: Match the weight

Start with a yarn in the same weight category as the pattern’s yarn. Then compare the length per 100 g (or per 50 g): yarns of a similar fiber with a similar length for the same weight are usually a similar thickness. The yarn weight chart shows the categories.

Step 2: Check the gauge

Crochet a swatch with the new yarn and the recommended hook, then measure it. If you have too many stitches, try a larger hook; too few, try a smaller hook. Matching gauge matters most for garments and anything that needs to fit.

Step 3: Compare fiber and texture

A cotton and a wool of the same weight will feel and drape differently. Think about what the project needs: structure for a bag, softness for a baby item, warmth for a hat. Our fiber guide compares the most common options.

Step 4: Work out how much you need

Always calculate by length, not by weight or number of skeins.

1. Multiply the number of skeins in the pattern by the length of each skein. For example, 4 skeins × 200 yd = 800 yd.
2. Divide that total by the length of one skein of your new yarn. For example, 800 yd ÷ 170 yd = 4.7.
3. Round up to the next whole skein — 5 skeins — and consider one extra for safety.

Why length matters more than weight

Different fibers have different densities. A 100 g ball of cotton is often much shorter than a 100 g ball of acrylic of the same thickness, so buying by weight can leave you short.

Dye lots

Yarn from different dye lots can differ slightly in color, even under the same color name. Buy everything you need — plus that extra skein — from the same dye lot.

When substitution gets tricky

• Garments depend on gauge and drape for fit. Swatch carefully and block your swatch.
• Amigurumi size changes with yarn thickness, and fuzzy yarns hide shaping.
• Novelty and textured yarns can hide stitch patterns entirely. Test a swatch before committing.