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Ultimate Guide to Aran Weight Yarn

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Looking for a comprehensive guide to aran weight yarn? You’ve come to the right place! In this blog post, we will discuss everything you need to know about this versatile type of yarn.

dark orange yarn and wooden knitting needles

Aran Weight Yarn

Aran weight yarn is a medium-weight yarn that is slightly heavier than worsted weight, but not as heavy as bulky weight yarn. Aran weight yarn is a great choice for a variety of projects, from sweaters and cardigans to hats and scarves.

  • CYC category 4, or Medium
  • 8 wpi, or wraps per inch
  • sometimes referred to as 10-ply yarn (often in Australia)
  • often used with 5-6mm needles

In this article, we’ll talk about the different types of aran weight yarn available and the benefits of using this type of yarn. So whether you’re a beginning knitter or an experienced knitter, read on for all the information you need about aran-weight yarn.

What’s the Difference Between Aran and Worsted Weight?

Aran weight yarn is often confused with worsted-weight yarn. While both are medium-weight yarns, there is a subtle difference between the two.

Aran yarn is slightly thicker than worsted-weight yarn, and knits up at a gauge of 16-18 stitches per 4 inches on 5mm needles. Worsted weight yarn, on the other hand, is slightly thinner and knits up at a gauge of 18-20 stitches per 4 inches on 4.5mm needles.

Click here to view a complete yarn weight yarn, with lots more information about all yarn weights.

Why it Matters

The difference of a few stitches may seem so small as to be inconsequential, but it can make a big difference in the finished product.

If you use a yarn that is too thick or thin for the pattern, it will be difficult to knit at the correct gauge, and your finished project may not fit as intended.

Here’s how it plays out: A difference of 2 stitches over 4 inches translates to a difference of 20 stitches over 40 inches – or a difference between a sweater that fits like a Medium and a sweater that fits like a Large.

So, if you want a sweater that fits, it’s essential to use the right yarn at the right gauge!

Regional Differences

Another thing to note is that the term “aran” is more commonly used in the UK, while the term “worsted” is more commonly used in the US.

If you are a British knitter using a US pattern, you can try substituting lighter aran-weight yarn for worsted-weight yarn.

In the same way, if you are a US knitter using a British pattern, you can try substituting a slightly heavier worsted-weight yarn for an aran-weight yarn.

skiens of orange yarn in a black and white basket

Can you substitute aran weight yarn for worsted weight yarn?

Aran and worsted-weight yarn are pretty similar, so you might be able to substitute one for the other in a pattern. You can generally swap a heavy worsted weight yarn for an aran weight yarn.

Of course, whenever you substitute yarn, we always recommend knitting a gauge swatch before starting your project. That way, you’ll know if your substituted yarn will work well with the pattern.

Our Favorite Aran Weight Yarns

Now that we know a little bit more about aran-weight yarn, let’s take a look at the different types available. The most common type of aran-weight yarn is wool, but you can also find yarns made from acrylic and cotton.

Wool Aran Yarns

One of the most popular types of aran-weight yarn is wool. Wool yarn is perfect for winter garments like sweaters and hats, as it is very warm and insulating. It is also great for felting projects. Wool yarn comes in a variety of colors, from natural shades like white and cream, to bright colors and everything in between.

Malabrigo Rios: Malabrigo yarns are a favorite among knitters, and it’s easy to see why. This yarn is super soft, has excellent stitch definition, and comes in a wide variety of hand-dyed colors.

Lion Brand Fisherman’s Wool: This classic undyed wool is perfect for knitting chunky fisherman-style sweaters.

Acrylic Aran Yarns

Acrylic yarn is a great alternative to wool, as it is less expensive and easier to care for. Acrylic aran yarn is perfect for projects that will be machine-washed, like baby clothes or afghans. It comes in a wide range of colors as well.

Lion Brand Heartland: This soft, premium acrylic comes in heathered and tweedy shades.

Cascade Pacific: This acrylic-wool blend is machine washable and dryable for easy laundering.

Cotton Aran Yarns

Cotton aran yarn is a good choice for summer garments, as it is cool and breathable. It is also a good choice for people with wool allergies. Cotton yarn comes in solid colors and variegated shades.

We Are Knitters Pima Cotton: This supersoft yarn is made from 100% cotton sources from Peru.

Wool and the Gang Shiny Happy Cotton: This cotton yarn is soft and sleek with a beautiful drape.

balls of yarn on a white background

More Yarn Guides

After reading this guide, you might be interested in learning about other types of yarn.

What’s Next?

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Sunday 23rd of April 2023

Could you include Australia in your comparisons as our crocheting and knitting mediums vary to the US and UK As trying to match wool to patterns becomes very difficult

Sarah Stearns

Monday 24th of April 2023

Hi Pauline, Yes, that would be a good addition.


Saturday 19th of November 2022

Owning a yarn shop for the past 22 years in Canada, I can agree with most of what you say. Aran yarn (whether wool from a sheep or yarn from other fibres) will produce a standard 18 stitches using a 5 mm needle in a 10 cm square stocking stitch section of a 15 cm swatch - always make the swatch bigger and measure the centre 10 cm. Standard worsted yarn is measured as 20 stitches in 10 cm on 4.5 mm needles. 16 stitches is usually considered chunky.

This is not to be confused with the over-generalized American category 4 that has such a wide range. ALL of my customers get confused with this number and ALWAYS end up with results they don't like - and frankly I deter everyone from using this measuring system. It is more important to look at the gauge listed on the ball band and compare it with the pattern's instructions (and of course still do a tension swatch to ensure you are knitting to the right gauge).

Patterns written for Aran weight yarn can certainly be interchangeable with worsted yarns to get correct gauge by adjusting needle size, but the finished fabric will be much different when it comes to drape, thickness and appearance. Using Cascade worsted yarns will always produce thinner fabric and will appear very drapy and with bigger looking stitches, while aran yarn gives a firmer and substantial fabric.

N.B. aran can also refer to colour and a type of sweater (made from the Aran Islands in Ireland also known as fishermen sweaters).

Sarah Stearns

Saturday 19th of November 2022

Thank you for your thoughtful comments. You bring up a great point about the differences in the final fabric when substituting worsted for aran yarns, or vice versa. The quality of the finished fabric is very important to consider, and another reason why swatching is essential!