Pick a yarn in the same weight category as the original, compare the yardage per skein, work out how many skeins cover the pattern's total yards, and knit a washed swatch to check you reach the pattern's gauge. Buy by yardage, not by weight.
A Norwegian version of this page is available on Strikketips.no
You might be substituting because the original yarn is discontinued or hard to find, because you want a different fiber or price point, or because the stash already has something close. The method is the same either way: two numbers decide whether a substitute can work — the weight category and the yardage — and a swatch decides whether it actually does.
Step 1: Match the weight category
A pattern is written for a gauge, and the yarn weight category tells you which gauge range a yarn is designed for. In the US the categories are the Craft Yarn Council's 0–7, from Lace to Jumbo. Start your search in the same category as the original yarn — a DK pattern wants a DK substitute.
If the pattern only names the yarn, look up its gauge on the label or the manufacturer's page and compare it with the yarn weight chart. Worsted and aran both sit in category 4; aran vs. worsted covers when the difference matters.
Step 2: Compare yardage, not weight
Yardage is how much length is in a skein, and it is printed on the label in yards or meters per skein. A pattern uses length. Two skeins that both weigh 3.5 oz100 g can hold very different lengths — a thin yarn packs more yards into the same weight than a thick one — so the weight on the label tells you almost nothing about how many skeins you need.
Within one weight category, yardage still varies from yarn to yarn. The spread among the yarns in our own catalog, normalized to 1.76 oz50 g:
| Weight | Yards (meters) per 1.76 oz (50 g) | Yarns counted |
|---|---|---|
| Lace | 458–470 yd (420–430 m) | 2 |
| Fingering | 219–220 yd (200–201 m) | 3 |
| Sport | 164–170 yd (150–156 m) | 2 |
| DK | 136–179 yd (125–165 m) | 4 |
| Worsted | 84–140 yd (77–128 m) | 8 |
| Bulky | 52–55 yd (48–50 m) | 2 |
| Super Bulky | 30–37 yd (27–34 m) | 3 |
This is a count of the yarns we list on popular yarn brands, not a standard — the Craft Yarn Council publishes gauge per category, not yards per ounce. The label on the yarn you're holding is always the number to use.
Step 3: Work out how many skeins you need
New skeins = (pattern's skeins × yards per skein) ÷ new yarn's yards per skein
The pattern calls for 5 skeins with 190 yd174 m each. Your substitute has 220 yd201 m per skein.
Total: 5 × 190 yd = 950 yd5 × 174 m = 870 m
New skeins: 950 yd ÷ 220 yd = 4.3870 m ÷ 201 m = 4.3 → 5 skeins
Always round up. Running out a few inches from the end costs more than a spare skein, and a later dye lot may not match.
The yarn substitution calculator does this for you, in yards or meters.
Step 4: Think about the fiber
The same yardage and gauge in a different fiber gives a different garment. What our fiber lexicon says about four common fibers:
- Wool (Sheep): Warm, Temperature regulating, Elastic, Odor resistant.
- Cotton: Cooling, Durable, Absorbent, Heavy.
- Alpaca: Very warm, Lanolin free, Silky soft, Lacks elasticity.
- Acrylic: Affordable, Non-itchy, Machine washable, Colorfast.
Cotton has no natural elasticity, so ribbing and fitted shapes that rely on wool's stretch will behave differently. A cotton garment can also both shrink and stretch in the wash. Swatch, wash the swatch, and judge the fabric before you commit.
Step 5: Swatch before you buy the lot
A substitute in the right category with the right yardage can still knit up to a different gauge on your needles. Buy one skein, knit a swatch in the pattern's stitch, wash and dry it, and compare with the pattern's gauge. Too many stitches: go up a needle size. Too few: go down. If no needle gives both the gauge and a fabric you like, the substitute isn't the right yarn for this pattern.
The full method is in how to knit a gauge swatch, and the gauge calculator tells you which way to change needles.
Frequently asked questions
Can I substitute any yarn in a pattern?
Usually, if the new yarn is in the same weight category, reaches the pattern's gauge on your needles, and you buy enough yardage. Patterns that depend on a particular drape, halo or stitch definition are more sensitive — the fiber matters as much as the numbers there.
What matters more when substituting yarn — weight or yardage?
For how much to buy: yardage. Two 3.5 oz (100 g) skeins can hold very different lengths of yarn, and a pattern uses length, not weight. For whether the yarn will work at all: the weight category and your swatch.
How do I calculate how much substitute yarn to buy?
Multiply the pattern's skeins by the yardage per skein to get the total yards, then divide by the yardage per skein of your new yarn and round up. The yarn substitution calculator does it for you.
Do I have to swatch when substituting yarn?
Yes. Two yarns in the same category can knit up to different gauges on the same needles. The swatch is what tells you whether the substitute reaches the pattern's gauge — and whether you like the fabric it makes.
Can I substitute cotton for wool?
You can, but expect a different garment. Cotton has no natural elasticity — in our experience cotton ribbing doesn't pull in the way wool ribbing does — and a cotton garment can both shrink and stretch in the wash. Swatch, wash the swatch, and decide whether the fabric suits the pattern.
Weight categories follow the Craft Yarn Council's Standard Yarn Weight System. Yardage for specific yarns is taken from each manufacturer's own product pages rather than from retailer listings.