Typically patterns suggest that you knit a gauge swatch by casting on 20 stitches and knitting 20 rows...PLEASE don’t do that! Here’s why…
20 stitches and 20 rows is a standard that has been adopted by the industry. It DOES NOT insure an accurate gauge. It simply is not enough stitches and rows for the average knitter to relax and knit as they would if they were knitting a larger project. As we knit, our hands relax, we think about other things, and our knitting tension changes. I say this from experience. Trust me: It’s worth the extra time to knit a larger swatch.
To knit a more accurate gauge swatch, cast on at least 40 stitches, and knit at least 40 rows using the needles suggested on the yarn label.
I know that it is tedious to knit 40 rows, but the correct gauge is important. I ask that it be knit at the time of day and place where you normally knit...in front of the TV or with friends, or after a glass of wine ;)...It can make as much as 1/2 stitch per inch difference. And, at 200 stitches, that's as much as 4". I can't tell you how many times I have knit 4 or 5 inches in the round and then calculated that I had 50 inches at the hips instead of 42 inches.
SO...I can't make you knit 40 stitches for 40 rows, but now you know why I ask...enough lecture...sorry…
How to measure the swatch
Take the swatch off the needles, lay it flat on a fabric surface. An ironing board or a sofa cushion works well. The fabric holds the swatch in place where a smooth surface allows the swatch to curl and slide. Measure gauge in the center towards the top of the swatch.
Is the swatch a true measure of your gauge?
When you lay the swatch flat, notice whether the swatch is rectangular, or if it is smaller at the cast on edge and “grows” wider toward the live stitches. If it is rectangular, this means that your stitches are consistent and that the measured gauge is correct. If it is not rectangular, it shows that you relaxed as you knit and your stitches loosened. In this case, continue knitting an additional 4 inches and measure again.
What if my gauge is different from the target gauge?
No problem! You can adjust the needle size until you have a swatch that feels soft and drapey without being too loose. You may already know that you knit looser or tighter as a rule. Just make sure that your gauge is consistent and enter that gauge in the custom pattern form.
Should I wash the swatch before measuring?
Yes! Different fibers will react in different ways to washing. If you are using a wool or wool blend, wash using the safest method (as recommended on the label). This should not have much effect the gauge swatch. However, non-wool fibers such as cotton, linen, silks and washable fiber blends may shrink, or at the very least, re-shape with washing and drying. It is important to wash the swatch as you intend to care for the finished garment before measuring gauge.