Knitting Tool
Yarn Substitution Calculator
How many skeins of the new yarn, based on length rather than weight.
How to use the calculator
- 1 Original yarn
Find the length per skein and total skeins specified in your pattern.
- 2 Substitute yarn
Enter the length per skein for the alternative yarn you plan to use.
- 3 Get result
See how many skeins to buy, rounded up to whole skeins.
Result: Yarn Substitution
Yarn Substitute Calculator
Find out exactly how many skeins you need when switching to a different yarn. Our substitution calculator accounts for different yardages and weights.
A Norwegian version of this page is available on Strikketips.no
Why use a yarn substitute calculator?
There are plenty of reasons to substitute yarn in a pattern: the original is hard to get or costs more than you want to spend, you don't get on with wool, or you've found a color you like better in another yarn.
A yarn substitute calculator works out how much of the new yarn to buy. The mistake it prevents is buying the same weight of the new yarn as the pattern lists for the old one. But if the original yarn has 164 yards150 m per 1.75 oz50 g, and your new yarn has 131 yards120 m per 1.75 oz50 g, the same weight gives you a fifth less yarn, and you will run out.
So the number to match is the total yardage, not the weight or the number of skeins.
How to convert yarn manually
The calculator does this:
Formula for yarn substitution
Number of alternative skeins = (Number of original skeins × Yardage of original yarn) ÷ Yardage of new yarn
Example
Say the pattern requires 8 skeins (1.75 oz50 g each) with 164 yards150 m per skein, and you want to switch to a yarn with 219 yards200 m per 1.75 oz50 g skein:
- Calculate total length of original yarn: 8 skeins × 164 yd150 m = 1,312 yards1,200 m
- Calculate number of new skeins: 1,312 yd ÷ 219 yd ≈ 5.991,200 m ÷ 200 m = 6 skeins
You need 6 skeins (10.5 oz300 g) of the new yarn, although the pattern asked for 8 skeins (14 oz400 g) of the original, because the new yarn has more yards per skein.
Round up to the next whole skein; the calculator does. The example comes out at exactly 6, and we'd still buy a seventh — swatching and gauge differences use yarn too, and a skein from a later dye lot may not match.
What yardage doesn't tell you
The significance of fiber content
Matching the yardage gets the amount right, not the fabric. In our experience wool springs back into shape, while cotton and linen are heavier and drape or sag. We'd choose a substitute with a fiber close to the original's.
Yarn substitution checklist
- Check the gauge: the alternative yarn should have a similar suggested gauge to the original. If yours comes out different, the gauge calculator converts the pattern's stitch counts.
- Consider texture: A smooth yarn will give a completely different look than a halo/mohair yarn, even if the yardage matches.
- Knit a swatch: even if the yardages match, your tension can differ between fibers.
- Buy extra: we'd rather have one skein too many. Ask the shop whether it takes back unopened skeins.
- Check care instructions: If the original yarn is superwash/machine-washable but the alternative requires handwashing, this may affect your final choice.
What does yardage mean?
Yardage (or length) tells you how many yards (meters) there are per 1.75 oz50 g or 3.5 oz100 g of yarn. Two yarns of the same weight can hold very different lengths, so when you switch yarn it's the length you need to match.
Can I switch to a yarn with a different gauge?
We'd pick a yarn with the same suggested gauge as the original. If yours differs, knit a swatch; the gauge calculator can then convert the pattern's stitch counts to your gauge.