How to Measure Your Knitting Gauge with a Swatch
Knitters are not all alike. Ask two people to knit the same pattern with the same pair of needles and yarn, and you will find that their work is a signature imprint of themselves. Some of us are loose and relaxed, so our knitting is loose. Others are tense and taut, so our knitting is tense and taught.
Gauge resolves our differences. It's also the first step of any knitting project to ensure that the dimensions of your finished piece will be correct. This is the number of stitches and rows per inch using a particular stitch, weight of yarn, needle size, and how you control them together. Typically, the gauge is given for a four- or six-inch square. In most gauges, the number of stitches per inch is less than the number of rows per inch. (For example, five stitches may equal one horizontal inch, whereas six rows may equal one vertical inch.) To determine the number of stitches you need to cast on for six inches of knitting length, multiply the number of stitches in one inch of knitting (specified by your instructions) by six. So, for our basic scarf project, which specifies four stitches per inch, you will need to cast on 24 stitches.
Consider yarn substitutions: A different yarn can affect the gauge as well as produce a different texture, especially with bouclé and mohair. Even gauges using the same weight of yarn may differ from color to color. The type of needle you choose can alter the gauge as well. You may obtain a different gauge using metal needles as opposed to bamboo or acrylic ones. That's why it's crucial to use the same yarn and needles for your swatch as you do for your project. Each knitter also has a different way of controlling the yarn, so be mindful of how you hold the needles, style of knitting, and the tension in your hands. All of these factors combined will affect the produced swatch.
How to Knit a Gauge Swatch
In a knitting pattern, the gauge will read something like this, "13 stitches equal 4 inches in stockinette stitch." Using the needles and yarn suggested, cast on the number of stitches required to get at least four inches. Frequently, this is stockinette stitch. However, follow accordingly if a more specific pattern stitch is suggested. If you are knitting many different stitch patterns in one garment, make one large swatch that incorporates all of the stitch patterns. Instead of casting off the last row of your swatch, place it on a stitch holder before removing the needles. This is because casting off will pull in your top stitches and change the size of your swatch. Note that this process is different for knitting in the round. To make an accurate swatch for circular knitting, you must knit every row (and not purl) with double-pointed needles.
How to Measure Your Gauge
Check your gauge by measuring the swatch. Since the stitches at the edges tend to curl inward or become misshapen, we recommend blocking the swatch before measuring it. Measure using a roll of measuring tape or stitch gauge tool. If you use measuring tape, measure just the inner four inches of the swatch. Place the tape parallel to a row of stitches, and count how many stitches fall within these inner four inches, including half stitches. Divide this number by four, and compare it with the specified gauge (four stitches to one inch). If you use a stitch gauge, position it in the center of the swatch, and count the stitches and rows inside the window cut-out.
If your gauge matches accurate measurements, proceed with your knitting. If your gauge doesn't match, try knitting another one with a different needle size. If your swatch is too small, then try larger needles. If it's too large, then try smaller needles. Label each swatch with the needle size, number of stitches, and gauge to keep in a knitter's journal for future reference. Just remember that if you do not achieve the exact gauge, you will be changing the size, texture, and overall feel of your custom knit piece.