Why is tension important?

Thursday 16th July 2020

Tags: Techniques

Have you ever had the experience of knitting something to the correct size in the pattern to discover you have created a miniature sweater or a cardie that completely drowns you? Dare we ask whether you checked your tension before you started?

Knitting or crocheting to the correct tension is essential if your project is going to come out the same size as the pattern. All the numbers in the pattern for rows, stitches, decreases etc have been worked out using a specific tension – if your tension doesn’t match then neither will the measurements. And if you substitute a yarn, it is even more essential because you can’t assume it will behave exactly the same as the yarn in the pattern.

Imagine if you were building a house and instead of using the bricks specified, you used ones that were slightly smaller or slightly larger. Being a couple of stitches out on tension might not seem like a lot, but when you think about a whole garment it can make a significant difference.


Getting the right tension

We used Special DK to knit these three squares on 4.5mm, 4mm and 3.5mm needles to show you what a difference being too loose or too tight can have on your project.  The tension on the ball band for this yarn is 22 stitches and 30 rows to 10cm on 4mm needles. We measured our squares in several places using a tape measure and took an average of the number of stitches and rows in 10cm.

The piece knitted on 4.5mm needles gave a tension of 20sts and 28 rows. This would mean your project would be around 10% bigger than the pattern states. So, if you were knitting a 34” chest garment it would be nearly 2 sizes larger.

The square knitted on 4mm needles came out to tension.

The square knitted on 3.5mm needles gave a tension of 24sts and 32 rows. In this case your project would be around 8% smaller than the size given in the pattern. If you were knitting a 34” chest garment it would be nearly 2 sizes smaller.

You can see why it is well worth taking the time to check your tension. If you find your tension is looser than stated, knit a new tension square using a needle one or two sizes smaller. If your work is tight and you have too many stitches and rows to 10cm try going up a needles size.

In most cases if you can only get one of row and stitch tension correct, it is better to choose the needles that give you the right stitch count. This is because patterns often ask you to work to a certain length, rather than a number of rows, which will allow you to compensate for having a slightly different number of rows to 10cm.