Substituting yarn can feel a bit like a gamble at first—but once you understand the basics, it opens up a whole new world of creativity. Whether you’re working from your stash, adjusting for budget, or simply falling in love with a different fibre, here’s everything you need to know to substitute yarn with confidence.
Why Substitute Yarn?
There are plenty of reasons to swap out the suggested yarn in a pattern:
- You can’t find the original yarn locally
- It’s discontinued or out of budget
- You want a different fibre (hello, wool allergies!)
- You’re customizing the look, drape, or feel
The key is making sure your substitute behaves similarly to the original.
Step 1: Match the Yarn Weight
The most important place to start is yarn weight. This determines how thick the yarn is and directly affects the size of your finished piece.
Common yarn categories include:
Substituting within the same weight category is the safest route. Going heavier or lighter can dramatically change sizing and structure.
By using the Yards divided by Grams equation, you will be able to tell how dense or thick the yarn truly is.
For Example: You have a pattern that uses Lion Brand Heartland but you want to substitute it with the Caron Simply Soft instead:
Lion Brand Heartland 251 yds /142 g = 1.77
Caron Simply Soft 315 yds/170 g= 1.85
The difference is 1.85-1.77= 0.08
Both of these yarns are Worsted Weight 4, but the numbers tell a different story.
Lion Brand Heartland is thicker than Caron Simply Soft, even though the label weight is the same.
When comparing yarns
• A higher number means the yarn is thinner
• A lower number means the yarn is thicker
• Numbers close together indicate a better substitution match
This simple equation is one of the most accurate ways to evaluate yarn.
If the difference is between 0.10 to 0.15 is usually safe
Step 2: Check the Gauge
Gauge is everything when it comes to fit and sizing.
- Patterns usually list something like: “4 inches x 4 inches” swatch = 20 stitches x 28 rows
- Your goal is to match this as closely as possible
Even if two yarns are labeled the same weight, they can behave differently. As explained above, a yarn marked as a Number 4 Worsted Weight might be slightly thinner in one brand and dense and sturdy in another. The same goes for every weight class.
—so always:
✔️ Make a swatch
✔️ Measure carefully
✔️ Adjust hook/needle size if needed
Step 3: Consider Fibre Content
Fibre affects how your project looks, feels, and wears over time.
Here’s a quick guide:
- Wool: Warm, elastic, great for garments
- Cotton: Breathable, less stretchy, great for summer wear
- Acrylic: Budget-friendly, easy care, less breathable
- Alpaca: Soft, drapey, warmer than wool
- Blends: Combine benefits of multiple fibres
👉 Example: Substituting cotton for wool in a sweater will change the drape and stretch—sometimes significantly.
Step 4: Yardage Matters
Don’t just match skein count—match total yardage/meters.
- Compare how many meters the pattern calls for
- Check your substitute yarn’s yardage per skein
- Calculate how many skeins you’ll need
This avoids running out halfway through (the ultimate heartbreak).
Step 5: Look at Texture & Ply
Texture changes the overall look of your stitches.
- Smooth yarn = crisp stitch definition (great for cables & lace)
- Fuzzy yarn = softer, more blended look
- Single ply vs multi-ply affects durability and structure
👉 If your pattern features cables or intricate stitches, avoid overly fuzzy yarns.
Step 6: Think About Drape
Drape determines how your finished piece hangs.
- Structured projects (bags, baskets) → sturdier yarn
- Flowy garments (shawls, wraps) → softer, drapier yarn
Swapping a stiff yarn for a drapey one (or vice versa) can completely change the finished result.
Bonus Tip: When It’s Okay to Break the Rules
Not every substitution needs to be perfect.
- Scarves, shawls, and blankets are forgiving
- Garments and fitted items require more precision
If you’re experimenting, start with low-risk projects and build confidence from there.
Final Thoughts
Yarn substitution isn’t just a workaround—it’s a creative skill. Once you get comfortable reading labels, understanding gauge, and comparing fibres, you’ll feel much more in control of your projects.
And honestly? Some of the most beautiful pieces come from unexpected yarn choices.
