Why and how to gauge swatch: a knitter's guide

To swatch or not to swatch, that is the question.

Why swatch? The most obvious and important reason is to make sure that you end up with a project that fits. We’ve all done it, just going about our lives YOLO-ing a project only to find out that it doesn’t fit after hours and weeks of work. 

But it’s not just a means of making sure that you’ve achieved the pattern’s stitch and row gauge—your swatch will also let you preview your fabric and decide if you’re happy with it. Different yarns will behave differently when knit up, and it’s not just a difference between superwash and non-superwash but also between worsted and woolen spun yarns.

So what does the swatch tell you about the knitted fabric?

When you swatch, you get to know the ‘hand’ of the knitted fabric—is it too drapey? too firm? how’s the stitch definition? Unsure about whether you’ll like the fabric next to your skin? Tuck the swatch into your clothing and wear it around for a while. 

Will it pill the instant it’s off the needles? Rub it vigorously against the leg of your jeans and you’ll find out. And since even a solid color yarn can look quite different between the skein and the knitted fabric, you also get to see what the color you’ve selected looks like knitted up.

How much swatch is enough swatch?

Make a generously sized gauge swatch in the pattern stitch—at least 6" / 15.5 cm square as best practice. Your swatch should be large enough that you can measure 4"/ 10 cm of undistorted stitches in each direction. Since stitches can be a little wobbly and loose at the edge of the swatch, or where you change from one stitch pattern to another, making a square that’s big enough to measure without the ruler touching any edge stitches is key. If the pattern calls for your gauge to be measured in the round, we suggest using this method to swatch.

I’ve knit the world’s biggest square, now what?

Washing and blocking your swatch is a must. Once you’ve completed your swatch, take a minute to not only measure your gauge but also measure it edge-to-edge in both directions. Make a note of the overall dimensions before you wet-block it. Keeping notes on the before and after measurements will allow you to predict what will happen when you wash and block your garment. 

Note: you should block your swatch in the same manner you will block and launder your final garment. In other words, if you plan on steaming the garment, you should steam the swatch.

Lay your swatch on a flat surface, patting it into shape. We only recommend using pins for lace work. You are not seeking an “aggressively blocked” gauge but the gauge that the yarn “wants to be at.” Allow your swatch to dry fully before measuring gauge. We recommend letting the blocked swatch “rest” a day or two after it is dry before taking final measurements, as the stitches can continue to contract until it is bone dry.

Help! I’m not getting gauge.

If you are not getting both stitch and row gauge, you will have to go back to the drawing board. Be sure to use “fresh” yarn rather than frogging your already knit and blocked swatch. This will ensure that your fabric will block out exactly as it will in the knitted garment. It will also be a good way to compare how changing needle size - and possibly material - will affect your overall gauge. 

While it’s important to always obtain stitch gauge, a great number of our (and other designers’) patterns also heavily rely on row gauge. If you are meeting stitch gauge but are unable to meet row gauge:

• Try swatching in a different material needle: If it’s within your means and you already have a different material needle in the size with which you are obtaining stitch gauge, switching between metal and wood needles may solve the row gauge discrepancy.
• Try using a smaller needle for purling: If you are knitting flat and utilizing interchangeable needles, using a needle 0.5mm smaller as your purl needle may help prevent “rowing out” where knit rows are tighter and purl rows are looser.

I’ve made the tiny square, now what?

Amazing! You’re now well on your way to knowing that the project you will make will be one that will fit - as long as you’ve chosen the correct size of course. 

Check your gauge multiple times over the course of the knitting to make sure you're still on track. You should be meeting your pre-blocked gauge as you knit, and blocked gauge as you complete any mid-project blocking.

So…my swatch lied.

Oftentimes this happens for a number of reasons, sometimes more than one. First, you didn’t make a swatch that was large enough. Or, you rushed making your swatch in order to cast-on that new project. Your gauge may even change over the course of a project due to stress levels (ask Aimee how she knows–she once knit socks that were two different sizes over the course of a pregnancy just due to wrist tension problems). 

So how do you prevent this from happening? Aimee and I have differing opinions, but it all comes down to your state of mind.

You should always swatch when you are in a relaxed state. If you’re a weirdo like me, you can have swatch parties while catching up on your reality TV with no particular project in mind (or very loose ones). I often like to play with yarn and just try out knitting different gauges and stitch patterns to see how I will like the fabric. 

If you are more of a planner like Aimee, we recommend swatching while you’re completing your final blocking session on your current make. You will have some time to kill while it dries and be able to cast-on that next sweater the second you’ve bound off that neckband and given it a good steam block.

Additional Tips

• Always use a rigid ruler to measure your swatch. Aimee has already written a helpful article outlining why here.
• Swatch using the same needles you plan on using in your pattern. Changing the needle tip length or material will alter your gauge.
• Unless swatching for a hat, use a 24” cord length or longer when knitting your swatch (even when knitting with shorties).
• A 2-row or 2-stitch garter edge around your entire swatch will help it to lie flat while blocking (simply add 4 stitches to your cast-on count).
• When knitting socks, you should still check your gauge! Knit your sock with your preferred needle size for a few inches. Place the live stitches on spare yarn or cording and block over sock blockers to assess gauge.
• Don’t stretch that swatch.

But I don’t want to swatch.

Both Aimee and I have situations where we just… won’t swatch! And here are some situations where we kind of YOLO it: 

Aimee: OK, I guess I don’t always swatch. I will pretty much never swatch for accessories, as that first finished object IS the swatch. 

If there are garment components that happen to be the size of a swatch (say, a large pocket, or the first 8 inches of a sleeve piece in a seamed garment… yet another reason to knit seamed stuff), then you can totally just use that as a swatch. Block that pocket or half-finished sleeve just like a swatch, and carry on. 

Use your best judgment when you follow tips like this! 

Aimee will often skip a gauge swatch and just measure from a previous project, if it’s a yarn they’ve worked with before. This is why you’ll often see them design with the same favorite yarns over and over (shh, don’t tell anyone). 

Mia: Now am I saying that I will always gauge swatch? Absolutely, not. And this is a lot coming from someone that genuinely loves to swatch (I’m not weird, right?). When knitting a pattern for the second, third, or even fourth time or one from a designer whose work I’m familiar with, I might still choose to live the YOLO life. 

But in these situations, I will also go in with the understanding that my garment becomes the swatch. I will be prepared to complete mid-project blocks and rip back if the garment is not working up according to plan. And I’ll understand that my lack of preparation in riding that new cast-on feeling may lead to a garment that takes more time to knit (and re-knit) or doesn't work out at all in the end.

Want to learn more? Here are a few more blog posts we have for you.

• Swatch without fear: your questions answered
• How to choose a size to knit
• Lace knitting tips for beginners