Practical guide 3 min read
How to substitute yarn in a knitting or crochet pattern
Buy by length, not skeins or grams, check the thickness with yards per 100 g, and hold thinner yarns double, with worked examples.
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Tool
Yarn Substitution Calculator
Enter what the pattern calls for and the yarn you want to use. You get the skeins to buy, what’s left over, and a thickness check based on yards per gram, so you know before you start whether the two yarns will behave alike.
Loading Yarn Substitution Calculator…
Runs in your browser. What you enter is saved on this device only.
How to use the Yarn Substitution Calculator
- Enter the pattern’s yarn: how many skeins it calls for and the length and weight of one, from the materials list. Or switch to a total length if that’s what the pattern gives.
- Enter your yarn’s length and weight per skein, from its label.
- If you’ll hold two strands together, set that; the length you need doubles.
- Buy the skeins shown, then swatch to check you can match the pattern’s gauge.
How it’s calculated
Length needed = the pattern’s skeins × length per skein (or its total length), plus any extra you add, times the strands you hold together. Skeins to buy = length needed ÷ your skein’s length, rounded up. Thickness is compared as yards per 100 grams: your yarn’s figure is divided by the strands held together and compared with the pattern yarn’s. Under 10% apart is a close match; over 20% usually changes the gauge noticeably.
Questions
Why compare yards per gram instead of the yarn weight name?
Names like DK and worsted cover a range, and brands use them differently. Yards per 100 grams shows how thick a yarn really is: two yarns within about 10% of each other usually work up alike. Fibre matters too, since cotton is heavier than wool and shows fewer yards per gram at the same thickness.
Can I hold two thinner yarns together instead?
Yes. Two strands of fingering are roughly one DK, and two strands of DK roughly one aran. Set “Strands held together” to 2: the thickness check compares the doubled yarn, and you need twice the length.
Should I substitute by weight or by length?
By length. Two yarns can weigh the same and differ a lot in length, so buying the same grams can leave you well short. The calculator works in yards or meters and converts to skeins at the end.
What else should match besides thickness?
Gauge first: swatch with the pattern’s hook or needles and change size until you match. Fibre and construction change drape, stretch and stitch definition, so a plied wool and a cotton tape of the same thickness still make different fabrics.
Are my numbers saved?
On this device only. Each calculator remembers what you last entered, in your browser, so you can pick up where you left off; nothing is sent to our server. Reset puts the starting values back.
Do I need an account?
No. Every craft calculator is free to use without signing in, with no limits.
Related calculators
- Crochet Yarn Calculator How much yarn a blanket, scarf, hat or sweater takes, in yards, grams and skeins.
- Granny Square Blanket Calculator How many squares a blanket takes, its finished size, and the yarn for every colour.
- Craft Project Cost Calculator Add up materials, time and overhead to see what a handmade item really costs.
- Handmade Pricing Calculator Find a selling price that covers materials, your time, fees and a profit.
Part of Craft Calculators
8 free craft calculators: yarn for any crochet project, granny square blankets, yarn swaps, resin, candle wax, 3D print costs and handmade pricing.
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