Yarn Substitution Checker
Thinking of swapping yarns? Check the weight category and meterage match before you buy.
Original yarn
Candidate yarn
Good substitute
- Same weight category — the fabric and gauge should behave similarly.
- Length per 100g is close — you will need a similar amount of yarn.
This is a starting-point check, not a guarantee — always knit or crochet a swatch with the candidate yarn before committing to a full project.
How to use
- Enter the original yarn's weight category (e.g. Worsted, DK) and its length per 100g, found on the ball band or the manufacturer's page.
- Enter the same two figures for the yarn you are considering as a substitute.
- Read the verdict badge: Good means the swap is likely safe, Caution means it may work but needs a swatch, Unsuitable means the yarns are too different.
- Read the reasons underneath the badge to see whether the weight category, the meterage, or both are driving the verdict.
Good to know
- Weight category (Lace, Fingering, DK, Worsted, Bulky, etc.) is a rough band, not an exact match — two yarns in the same category can still knit up differently, which is why length per 100g is checked separately.
- Length per 100g (meterage) matters because it tells you how much yarn a given weight actually produces — a denser or airier spin at the same weight category can use noticeably more or less yardage for the same fabric.
- A "Good" verdict is a starting point, not a guarantee — always knit or crochet a swatch with the substitute yarn and check it against the pattern's gauge before committing to a full project.
FAQ
- What makes two yarns safe to substitute for each other?
- They should share the same (or an adjacent) weight category and have a similar length per 100g. Both signal that the substitute yarn will knit up to a similar thickness and use a similar amount of yardage as the original.
- My yarns are the same weight category but the verdict says Caution — why?
- Weight category and length per 100g are checked independently, and the worse of the two decides the verdict. Two yarns can share a category (e.g. both Worsted) yet have meaningfully different meterage, which changes how much yarn you need and how the fabric drapes.
- Can I trust a "Good" result without swatching?
- Treat it as a strong starting signal, not a final answer. Fibre content, ply structure and dye process all affect drape and gauge in ways a weight category and meterage comparison cannot fully capture, so a swatch is still the safest final check.
- Where do I find the length per 100g for my yarn?
- Check the ball band — many labels print total length and total weight (e.g. "220yd / 100g"), which you can convert to a per-100g figure. If the band only lists a different weight, scale it: divide the length by the weight in grams and multiply by 100.