Understanding Knitting Gauge ~ Why and How to Knit a Swatch

Knitting gauge can feel confusing at first, but learning how to knit a swatch is the best way to understand your own knitting tension and set yourself up for a successful project.

When I start a new project, I usually just want to dive right in. I sometimes used to skip knitting a swatch altogether. I thought it was a waste of time. But I learned the hard way that ignoring gauge instructions can mean your finished measurement is way off. For something like a jumper/sweater pattern, small differences in knitting tension can add up to a completely different size.

Gauge swatches are really the starting point for the success of your knitting project. They help you find the correct gauge before committing to a larger project.

And they don’t have to be wasted!

You can unravel them, reuse the yarn, or even sew a few swatches into little projects, e.g. beanbags for kids, or you could use them as dishcloths or doll blankets.

What Is Knitting Gauge?

Knitting gauge is simply the number of stitches and the number of rows you knit within a set measurement, usually 4 inches or 10 cm.

A pattern gauge might say something like 18 stitches and 24 rows = 4 inches in stockinette stitch. That’s the gauge of your pattern, and it’s based on the exact yarn and recommended needle size that the pattern designer used.

Your own knitting gauge might be tighter or looser depending on your knitting style. It also depends on your yarn weight (for example, fingering weight yarn, worsted weight yarn, or chunky weight yarn), different stitch patterns, and even different needle materials like bamboo needles or metal needles.

Why Gauge Matters

Gauge really does matter, especially for garments or anything that needs to fit. If you knit fewer stitches per inch than the pattern gauge, your project will turn out too big. If you knit more stitches, you’ll end up with a smaller piece.

Those small differences in stitch count can add up to different-sized pieces that don’t match the finished measurement listed in the pattern.

Gauge also affects yardage. A looser gauge often uses more yarn, which can lead to gauge problems like running out of yarn before you finish. On the flip side, a tighter gauge might leave you with leftovers. Either way, matching the recommended gauge is a good idea so you know you have enough yarn.

And don’t forget the row count. While stitch gauge is usually the most important, the number of rows (especially in patterns with purl bumps, rows of garter stitch, or colourwork) can make a big difference in the final look.

Once you understand gauge, you can even use it creatively. Choosing a different gauge on purpose, for example, using a larger knitting needle or a larger needle size to get a looser gauge, can give your project more drape. Or using a smaller knitting needle or smaller needle size can give a toy more structure.

female hand holding knitting needles and yarn on her lap cat sitting in the back

What Is a Swatch?

A swatch is a flat swatch (or sometimes knit in the round with circular needles) that’s basically a mini version of your fabric. It’s where you test your own knitting gauge against the gauge instructions in your specific pattern.

A general rule of thumb: make a larger swatch than you think you need, at least 4 to 6 inches square. That way, you can measure in the middle and not on the edge stitches, which are often uneven. Add a few extra stitches at each side so the center stitches give you a more accurate reading.

Some knitters like to add a border of purl rows or rows of garter stitch to help the swatch lie flat on a flat surface.

When you knit a swatch, use the exact yarn, recommended needle size (in US or mm needle sizes), and stitch pattern called for in the gauge section of the pattern.

If your first try doesn’t match, don’t worry. The general consensus among a lot of knitters is that you’ll need to try a different needle size to get the proper gauge.

Swatches can feel like a little bit of extra work, but they’re your moment of truth before starting your larger project. They’re how you make sure your finished piece looks like the pattern designer intended.

And as I said, making a gauge swatch doesn’t mean wasted knitting time. You can unravel and reuse the yarn, or save your swatches to turn them into something new (especially if you have kids).

blue knitted swatch with pins and measuring tape

How to Knit a Gauge Swatch

Making gauge swatches is simple, but there are a few things you can do for a more accurate reading:

Cast on extra stitches. If the pattern gauge is given over 4 inches, cast on enough stitches for at least 6 inches. Those edge stitches can be messy, and you want your gauge measurement to come from the middle of the swatch.
Work in the right stitch pattern. Check the gauge section of the pattern carefully. It might be in stockinette, garter, or even a more specific pattern. Follow the gauge instructions exactly.
Knit a larger swatch. Aim for 4–6 inches tall so you can measure both stitch and row count in the center. Some knitters add a few rows of garter stitch or purl rows around the edge to help the swatch lie flat on a flat surface.
Use the recommended needle size and yarn weight. Start with the recommended needle size on the yarn label or in the pattern. For example, if you’re knitting with worsted weight yarn, you might start with a 4.5 mm needle, but fingering weight yarn or chunky weight yarn will need a different needle size.
Block your swatch. Wash it and dry it the same way you plan to care for the finished project. This step often changes your knitting tension and gives you the proper gauge.
Measure carefully. Lay the swatch flat, place a tape measure across the center, and count the number of stitches and the number of rows within 4 inches (10 cm). This is the moment of truth: Your own knitting gauge compared with the standard gauge in the pattern.

What to Do If Your Gauge Doesn’t Match

It’s completely normal if your first try doesn’t give you the right gauge. Here’s what to do:

Too many stitches per inch (tighter gauge): Switch to a larger needle size or even a larger knitting needle. This will give you fewer stitches and a looser gauge.
Too few stitches per inch (looser gauge): Try a smaller needle size or smaller knitting needle to tighten things up and get more stitches per inch.
Row count doesn’t match: Often, this matters less than stitch gauge, but in some specific patterns (like colourwork or free knitting patterns with a set number of rows), row gauge is important. Adjusting with a different needle size or yarn weight might help, but sometimes you just need to keep an eye on the length as you knit.
Try different needle materials. Some knitters get a tighter gauge on metal needles and a looser gauge on bamboo needles or circular needles. Even a little bit of gauge change from different materials can make a difference.

If you still can’t match the exact gauge, you may need to use a thinner yarn or thicker yarn (switching from fingering weight yarn to worsted weight yarn, for example).

Common Mistakes to Avoid

Here are a few common pitfalls knitters run into with gauge swatches:

Not blocking the swatch. Without blocking, you don’t get an accurate gauge swatch. Knitters’ tension often relaxes after washing, which can change the finished measurement of a larger project.
Measuring edge stitches. Edge stitches curl or stretch, which throws off your gauge measurement. Always measure in the middle for a more accurate reading.
Making too small a swatch. A tiny flat swatch won’t give the proper gauge. You need a larger swatch for a true test.
Ignoring row count. While stitch gauge usually matters most, row count can affect shaping, colourwork, or the success of your knitting project.
Forgetting that small differences matter. Even one extra stitch per inch adds up in a sweater pattern.