With a few sweater classes coming up in the Spring semester, I wanted to give some pointers on gauge and swatching for those out there who may not have yet done this.
What is Gauge? Gauge refers to the number of stitches wide and rows tall that you need to knit to reach a certain number of inches. In general, gauge is given per inch or per 4 inches (10cm).
Examples of gauge: A ball of worsted weight yarn might say “16sts = 1 inch on US#8” This means that if you use US#8 needles and knit 16sts in this yarn, you should get a one inch wide piece of fabric. The back of most ball bands will reveal the suggested gauge of that particular yarn, when knitted in stockinette stitch with the suggested needle size. This site gives a great overview of the differences in yarn weight and gauge. It’s also linked from the “Community” section of my site.
Why swatch? A pattern will tell you exactly what gauge you should get with the yarn and needles they recommend. If you know the gauge, you can then substitute other yarns with similar gauge or change the needle size up or down to help get gauge. Because every knitter knits differently, you MUST knit a test swatch with your selected yarn and needles to determine if your gauge matches that of the pattern. If it doesn’t you could end up with a sweater that is too big or too small (and that is just a waste of time and money).
How do I swatch? First, use the needles indicated in the pattern and your selected yarn. Lets assume that our pattern calls for a gauge of 20sts per 10cm. I would cast on 25 or 30sts, so that I have plenty of space to measure four inches across. then work in stockinette stitch for five inches. Cast off and then block the swatch so that you are able to measure what the fabric will do after it is washed or blocked.
*Some fabrics expand or stretch after they are washed so it is important to know what your fabric is going to do after it is blocked. (Cabled fabrics in particular get much larger after then are blocked)
Below is a gauge swatch. To measure gauge, put a ruler over the swatch.
Now count the “V”s or stitches that span a one inch and then two inch or four inche span of the swatch.
This swatch shows a gauge of 5.5 sts per inch. Since we are getting 5.5 sts per inch, our gauge is 22sts per four inches. It would appear that we our gauge is off, as we have more stitches per four inches than the pattern calls for. To adjust, I could increase my needle size up one number, knit another swatch and measure again.
*It is also important to measure the rows per one or four inches, particularly if the pattern also gives this gauge.