How to knit a tension square and why it’s a good idea.

Yes, it is a good idea, so, if you’re one of the many who accidentally-on-purpose forget to knit your tension square, this blog is for you! It is not a waste of time to knit a tension square. Rethink your actions and remember ‘proper planning prevents poor performance’!

If you’ve never heard of a tension square, don’t worry, it isn’t as stressful as it seems. A tension square will, I promise, be your best friend.

What is a tension square and why should I use it?

The tension square is the building block of your pattern, the corner stone of your structure, the foundation of your item…oh you get the gist! It’s really quite important. A tension square is knitted to ensure the gauge on your knitted item is correct. As we discussed on our blog “How to read a knitting pattern”, the gauge for a knitted item is indicated on the knitting pattern. The gauge is the number of stitches your item should have per inch/cms.

Knitting a tension square is a very important stage of the process, especially if you are intending to change the wool size/type from the design. Essentially, it is a trial run for your knitted item, and is highly advisable if you are changing the wool or are a beginner knitter.

Items needed to knit a tension square

  • the yarn you will be using for your knitted item
  • the needles you will be using for your knitted item
  • a ruler
  • pins

 1. Knitting the tension square

The pattern will normally guide you as to how many rows/stitches or inches/cm to knit. You’ll need to knit roughly 10cm/4 inches. Knit your tension square in the same design stated in your patterns. If there are two or more designs in the knitted item, you might need to knit a tension square for each design.

It’s always a good idea to knit a square larger than stipulated. Leaving extra knitting either side of the size required for tension square makes it easier to measure, as the sides of a knitted square are likely to curl up slightly, for this reason make sure to cast off loosely. Also, knitting a smaller square usually requires in a tighter knit.

So far, I have not addressed how to check your tension when you’re tackling pair of socks, or any other item that requires knitting in the round. Your tension is likely to be different when you are knitting in the round from knitting on single points as sometimes we knit more loosely or tightly on wrong side rows. When you are knitting in the round, you are permanently on a right-side row. To test your tension when knitting in the round, you can fake a circular gauge tension square. Using two double pointed needles, cast on enough stitches as prescribed for a tension square by the knitting pattern, and add a few more each side for ease of measuring. Knit your first row. Instead of purling your second row, trail your wool round the back of your knitting so that you can knit your second row from the same side as your first row. Repeat rows one and two until you’ve created a square. Then you can cast off a begin measuring.

2. Measuring the tension square

First things first, measure your tension square off the needles. Cutting corners is not going to help you! Some instructions will suggest that you block and/or iron your tension square (on the cool setting), to prevent the sides rolling up, others will suggest that you leave the yarn to ‘rest’ for a couple of hours. As you’re likely to be tearing to go, we suggest you use a damp (and preferably clean) tea towel as a pressing cloth, then iron the tension square very lightly with the iron on a cool, wool setting. Whatever you do, it is important that you don’t stretch the fabric, it won’t help you in the long run!

Now for the measuring! This needs to be done on a level surface, with good lighting! It’s important the fabric doesn’t move while you’re measuring. It’s always a good idea to pin out your square before measuring, especially if you’re trying to measure a more complicated pattern.

A solid ruler will do the trick just fine, just don’t use a tape measure. Tape measures have a tendency to move when you’re not expecting it, and you want your measurements to be correct!

Measuring the rows can be difficult, if you’re working stocking stitch you can just count the ‘V’s. Luckily, it is the tension width wise is more important that the tension length wise. This is good to know if you need to correct one or the other

3. Correcting your tension

If, once your tension square is finished, the gauge is as indicated on the pattern, then hooray! Give yourself a pat on the back, you do not need to do any fiddly stuff. Get going on your project, but keep in mind you will still need to do a tension square for future projects. Just because your tension was on point for one project, does not mean you’ll be so fortunate next time around! Designers of knitting patterns tend to describe the tension according to the way they knit, so tension can vary from designer to designer and pattern to pattern.

Even if there is a slight deviation from the number of stitches to the measurement, it must be rectified. This slight difference, even by half a stitch, can make a whole size differences by the end of a jumper. You will have to change your needle size and try another tension square to check again.

If there are fewer stitches than recommended, it means you’re a loose knitter and that the finished item will be too large. If you want to stick with your current wool you need to change to smaller needles.

If your sample has more stitches than the instructions indicate the item will be too small, you must therefore use larger needles.

In regard to rows, if there are more than recommended, your garment will be too long whilst fewer rows will create a shorter garment than specified.

Make another tension square with your new needle size and repeat the whole exercise until you are getting the right number of stitches and rows specified by the pattern.


But do I really need a tension square?!!

You’d be silly not to trial run a knitted garment with a tension square. We all knit differently, just as we all write differently. You cannot assume that you’ll knit as loosely or a tightly as the person who created the pattern. Using a universal measurement for tension, is as an important as having a universal measurement of length. Never forgot the confusion of the medieval ages when each British town had a different length mile! Having the correct gauge is important if you are knitting a wearable item, you don’t want it to end up with completely the wrong size! It’s also highly advisable if you’re a new knitter.

The excitement of a new project can often rush us into knitting our item, without giving proper care and consideration for the details. We can all be guilty of it but, whilst this can lead to items being out of shape, it is this same passion and excitement which makes a keen knitter, so it’s not all negative!

Hopefully, we’d swayed you to the importance of knitted a tension square before diving into the rhythm of a new project. For the sentimentalists among you, why not keep your tension squares as a memento of projects (especially, if you tend to pass on your finished items to friends and family). Alternatively, if you don’t want a neat square to go to waste, find a way to use it in an unseen part of your item.