Yarn substitution: length, skeins and weight
A pattern uses a length of yarn. It prints that length as a number of skeins of one particular yarn, and the skeins of another yarn are longer or shorter. So the sum goes through length: skeins in the pattern times the length of one of them is the length needed; divided by the length of a skein of the substitute, and rounded up, it is the number to buy. Every guide we checked agrees on this, and on rounding up.
The usual mistake is in the units. Labels from Europe give meters, many patterns give yards, and a yard is about nine tenths of a meter. One magazine's guide spells it out: if you multiplied in yards, divide in yards. The calculator takes each length in its own unit and converts with 1 yd = 0.9144 m.
The bare answer leaves nothing for a swatch or for a slightly looser gauge. Guides suggest a tenth more, or one spare skein. The extra is an input, and the calculator shows how much yarn is left over either way.
Length is not the whole story. Two yarns with the same length in a skein can be very different in thickness if the skeins weigh different amounts. Length per hundred grams puts them on one scale: a substitute that is close to the pattern yarn on that scale, in a similar fiber, will usually knit to a similar gauge. A large gap means a different fabric, and the pattern's length no longer applies. Swatch before buying the lot.
Chart: skeins of the substitute to buy, by its skein length and the pattern's skeins
Each cell is the number of skeins to buy when the pattern calls for the number of two hundred yard skeins in its column and the substitute has the length in yards in its row, with no extra.
| Skeins the pattern calls for | |||||||
|---|---|---|---|---|---|---|---|
| Length of one substitute skein | 3 | 4 | 5 | 6 | 8 | 10 | 12 |
| 80 yd | 8 | 10 | 13 | 15 | 20 | 25 | 30 |
| 100 yd | 6 | 8 | 10 | 12 | 16 | 20 | 24 |
| 110 yd | 6 | 8 | 10 | 11 | 15 | 19 | 22 |
| 120 yd | 5 | 7 | 9 | 10 | 14 | 17 | 20 |
| 150 yd | 4 | 6 | 7 | 8 | 11 | 14 | 16 |
| 170 yd | 4 | 5 | 6 | 8 | 10 | 12 | 15 |
| 220 yd | 3 | 4 | 5 | 6 | 8 | 10 | 11 |
| 250 yd | 3 | 4 | 4 | 5 | 7 | 8 | 10 |
| 300 yd | 2 | 3 | 4 | 4 | 6 | 7 | 8 |
| 400 yd | 2 | 2 | 3 | 3 | 4 | 5 | 6 |
Used by
- Yarn substitution calculatorHow many skeins of a different yarn a pattern needs.