The importance of knitting gauge for sweaters

You know I am all about knitting sweaters—especially sweaters that fit perfectly. While I often say that gauge is the least common reason that sweaters don’t fit, gauge is still a factor. But how and when to change needle size for gauge isn’t as obvious as many imagine. I recently had Liz, a new member of Club Crazy for Ewe, reach out about gauge for our current club class project, the Ludham sweater, so I thought I’d do a bit of a dive into gauge generally and what to do if your gauge swatch isn’t just right.

What is Knitting Gauge?

Knitting gauge is the number of stitches and rows per inch. Gauge tells you how big or small your stitches are by identifying how many it takes to make 4 inches. Gauge can vary widely from knitter to knitter, so don’t just assume you will need the same size needle as the designer or your knitting buddy. Always check your own gauge and be sure you’re using the right-sized needle for you. Your own gauge will also vary depending on the yarn, so just because you get a particular gauge with a particular needle on a particular yarn does not mean that you will get the same gauge with the same needle on a different yarn. Always check your gauge with the yarn you intend to use for the project.

Why is Gauge So Important for Sweaters?

The gauge determines the size of the finished garment. If your gauge is too tight, your sweater will be smaller than intended. If your gauge is too loose, your sweater will be larger than intended. For example, if the back of the sweater in the size you have chosen has 100 stitches and the pattern gauge is 5.5 stitches per inch (22 stitches per 4 inches), you would be expecting a finished sweater with a finished bust of 36”. If your gauge is off by just a half stitch, say 5 stitches per inch instead of 5.5, you would end up with a sweater with a 40” bust. If you were off just half a stitch per inch in the opposite direction, your sweater could end up with a 33” bust. Depending on how you were intending the sweater to fit, either of these outcomes could be a huge disappointment. It’s always worth the time to swatch and check your gauge.

How to Check Your Gauge

The best way to check your gauge is to knit a gauge swatch. A gauge swatch is just a smallish piece of fabric you knit in the yarn you’ve chosen to see if the needles you’re using will give you the gauge called for in the pattern. Here’s how to knit a gauge swatch:

• Using the yarn you’ve chosen for your project, cast on the number of stitches the pattern says you should have in 4 inches plus 6 or 8 stitches. So if the gauge is 20 stitches per 4 inches, cast on 26 or 28 stitches.
• Start with the needle size recommended in the pattern. Unless you know you’re a tight or loose knitter, you can just start with the recommended needle and go from there.
• Knit in the stitch directed in the pattern for the specified number of rows. Always look to see what stitch pattern the gauge uses. It may be stockinette, but it may also be something else if your sweater has a large component of a different stitch pattern.
• Slip the stitches to waste yarn. Leaving your swatch stitches on the needle can skew the measurement, so just slip them to waste yarn. You can also just slip them off the needle if it’s not a slippery yarn.
• Measure your gauge swatch. In the center of your swatch, mark the number of stitches you are supposed to have in 4” and measure the width of those stitches. If they measure exactly 4”, you are golden with that needle. Hooray! Go cast on and get started.

What to Do If Your Gauge is Off

If your gauge is off, don't worry. You can totally fix it.

Is your swatch too wide?

If the marked number of stitches in your swatch measures more than 4”, it means that each stitch is a little bigger than it should be, and you will want to go down a needle size. You don’t need to rip out the first swatch; just work a purl row on the right side to show where you changed needles and knit another 4 inches.

Is your swatch too narrow?

If the marked stitches in your swatch measure less than 4”, your stitches are smaller than they need to be, and you may need to go up a needle size. But note that I said *may* need…

If your swatch is only a little too narrow…

Before you jump to a larger needle, look at how much too narrow it is. If your stitches are only a little bit narrower than needed, you might be best served by correcting the width during the blocking process. Check to see if your fabric is a candidate for this by easing the marked stitches out to 4 inches. If you can get gauge by gently easing (not stretching) your fabric out, stay with that needle size.

Consider Blocking

Blocking always evens out your stitches, and sometimes it can make the difference in a slightly too-tight fabric. I am a fan of steam blocking, so if I have a slightly too-tight swatch, I will pin it to the gauge it should be and give it a good steam. Then let it rest and re-measure.

A Word of Caution

Easing the fabric is a super helpful technique, but it's important not to overdo it. If you have to stretch the fabric such that it distorts the stitches, you need a larger needle. The key here is gentle easing—not stretching.

If you are in doubt about whether to ease your fabric out or go to a larger needle, try the larger needle and see if you get gauge with it, or if your swatch is too large. You are better on a slightly smaller needle with a slightly eased fabric than a fabric with a gauge that is too loose and lacking structural integrity.

TLDR

Gauge is important in sweater fit, and whether you need to go up a needle size isn’t always as clear cut as it might seem. In cases where it’s a close call, I generally advise knitters to err on the side of a fabric that is a smidge too tight rather than too loose, because knitted fabric stretches, and you can always block it larger. But there’s nothing you can do about a fabric that is too loose.

I hope this helps you as you swatch and think about fabric for your sweaters. I would love to hear your thoughts in the comments.

Warmly,
Ellen