Yes, at most times you can substitute a worsted yarn with an aran yarn and vice versa. I would say that it pretty much depends on the project you have in mind.
Let’s say that your knitting a blanket and swap the yarn for a slightly heavier or lighter alternative. Your gauge will probably change but if the blanket turns out a little larger or smaller than expected it’s not a big deal. In this case, the look and feel of the yarn and the knitted fabric will probably be more important than the sizing.
When to be cautious with substituting yarn
At other times, the gauge can be crucial for the final result. Let’s say you are about to knit a fitted sweater, if your gauge is off by a couple of stitches your sweater is likely to turn out too big or too small.
If you want to swap between aran och worsted weight yarns for a garment where fit is crucial you will have to make a swatch to measure your gauge. If the gauge is just a few stitches off you may be able to get around it by following the instructions for another size. Otherwise, you will have to recalculate the pattern or go with another yarn.
If you substitute an aran yarn with worsted yarn on the lighter side of the scale you will have to use larger needles than the recommended size to get the right gauge.
This may work, but the fabric will be thinner and more openwork than the pattern designer had aimed for and this will affect the way the finished garment drapes and sits on your body. You may be fine with it, and it may even be better, but there is also a risk that it does not work out.
And the other way around, when substituting a lighter yarn with a heavier one you will need to use smaller needles than recommended for the yarn to get the right gauge. This will result in a denser fabric with less flow and drape.
How to avoid problems when subbing yarn
These are just some bullet points to keep you from yarn subbing issues 🙂
- Always try to find a yarn that’s close to the original in weight, yardage/meterage
- Swapp between yarns of the same or similar fiber content. Wool is elastic and fluffy while cotton is inelastic and fluff free.
- Make a swatch. And when you have made it, wash it and let it dry before measuring and making decisions. I tend to be a bit hasty with this and it has caused me some issues. Do as I say, not as I do…
- Be super careful with projects where fit is vital.