We’ve all done it. Started knitting in the size we think will fit, followed the pattern and ended up with something that is completely the wrong size.
If only we’d knitted a tension square.
Knitting to the correct tension is essential if your piece is going to come out the same size as the pattern. This is because the tension stated in the pattern is the basis for how the pattern writer worked out all the sizes. And checking your tension is especially important if you are substituting a yarn – you might think two similar yarns might knit to the same tension but it isn’t necessarily so.
Getting the right tension
In the picture the 4.5mm needles gave a tension of 20 sts x 27 rows, 4mm was 21 sts x 28 row and 3.5mm, 23 sts x 31 rows for a 10cm square. I lightly steamed the squares and pinned them flat before measuring
This means that 105 sts would give you 50cm using the 4mm needles but 45.5cm on 3.5mm and 52.5cm on 4.5mm – (stitch number divided by stitch tension) x 10 = width.
So if the tension for the pattern was 21 sts for 10cm on 4mm needles but your tension came out as 20sts because you are a slightly looser knitter you could end up wit a garment several centimetres too big. The same is true for differences in row tension
In that case you should go down a needle size and knit a new tension square. If you have too many stitches and rows to 10cm try going up a needles size. Sometimes you need to try a couple of needle sizes to get find the right tension but the hassle of knitting some extra tension squares is nothing compared to ending up with a useless garment.
Knitting a different size
This solution involves more sums and is riskier because you may need to use length measurement from your original size to get a good fit but I’ll give you a quick explanation anyway.
If your tension was 23 sts to 10cm instead of 21cm your piece would be too narrow.
You work out how many stitches that you need for the correct width as follows:
[Width divided by 10] x stitch tension = [50/10] x 23 = 115 sts
So if one of the other sizes calls for 115 sts you might try knitting that in the hope all the shaping works. However, it is usually better to try different needle sizes to get a close as possible to the pattern tension.