How Many Stitches to Cast On for Socks (So They Actually Fit)
We’re breaking down how many stitches to cast on for socks—so your handmade pair fits like a dream, not a disaster.
Ever spent an entire evening casting on a pair of socks, only to realize your “snug fit” is a wooly slouch boot? Or worse—your cozy sock is cutting off circulation? Yep, I’ve been there, too.
In this post, I’ll walk you through everything you need to know about knitting socks that really fit—no matter the yarn, the pattern, or whether you're knitting for a man or a woman. You can use this guide to choose the right size in stitch-count-based patterns or to help you improvise your own socks from scratch.
It All Starts With Stitch Count
The number of stitches you need to cast on depends on several factors:
- The yarn you’re using
- The needle size
- Your personal tension
- And even the pattern itself
For example, ribbed socks require more stitches than plain stockinette socks because the ribbing pulls the fabric in. And, of course, bulkier yarns or a looser tension will require fewer stitches overall. All of these little differences matter—and they affect the final fit.
Gauge Is Everything
Yes, you should swatch. We know, but trust us, it saves tears later.
Swatching is the only way to truly understand your tension—and since your stitch count controls the fit, stretch, and comfort of the sock, it’s worth the effort. This is especially true when working with different yarn weights, sock patterns, or knitting methods (like magic loop or DPNs).
The good news? Once you figure out your magic numbers, you won’t have to swatch for every single pair of socks. But to get there, you’ve got to start by making a swatch now, using your chosen yarn and needles.
How to Swatch for Socks
- Knit a square measuring 10x10 cm (4x4 inches)
- Use the needle size you plan to knit your socks with
- Use the stitch pattern you’ll use for the socks: ribbing for ribbed socks, stockinette for stockinette
- Wash and dry your swatch flat—just like you’d treat the finished socks
The last step—washing your swatch—is really important, because yarn can change significantly after washing. If you skip this step, your handmade socks might fit perfectly at first, but only until the first wash.
And we don’t want that! We want socks that fit beautifully and stay that way—so you can enjoy wearing them for a long, long time.
Once your swatch has dried completely, count how many stitches you have per 5 centimeters (or 2 inches)—using the middle section of the swatch for the most accurate result.
Write it down—you’ll use this number to calculate your cast-on for the perfect fit.
Time to Measure Your Foot
There are a few different ways to measure your foot to calculate how many stitches you need to cast on for socks.
The most common method is to measure the ankle or leg circumference, depending on where you want the sock cuff to sit. This works well for longer socks.
But if you're knitting shorter socks, it's often more accurate to measure the widest part of your foot—usually around the ball of the foot.
Now for the Math!
Count stitches per cm/inch
Use your swatch to determine your stitch gauge. Divide the number of stitches over 5 cm (or 2 inches) by 5 (or 2) to get your stitches per cm/inch.
Example: If you have 20 stitches over 5 cm → 20 ÷ 5 = 4 stitches per cm.
Multiply by your foot measurement
Measure the circumference of your foot in centimeters or inches and multiply it by your stitch gauge.
Example: 4 stitches/cm × 22 cm = 88 stitches
Add negative ease
To ensure your socks fit snugly, subtract 10–15% from your total stitch count.
- Use 10% if you're a tight knitter
- Use 15% if you're a loose knitter
- Also, consider the stretchiness of your yarn
Example: 88 – 10% = approx. 79 stitches
Round to match your stitch pattern
Adjust your final number to the nearest multiple that fits your stitch pattern.
For example, if you’re using a 2×2 rib, round to the nearest multiple of 4.
Always choose an even number of stitches, especially if you’re working with ribbing or other repeat-based stitch patterns. It’ll make your knitting smoother and more consistent.
Cast On Your Socks
Now that you’ve calculated your stitch count, it’s time to cast on and get those socks started!
Knit the first 5–10 rows, then try it on to make sure it actually fits and feels good. This little check-in can save you from knitting an entire sock that doesn’t fit quite right.
The truth is, sock knitting is incredibly rewarding once you find your rhythm—and your perfect stitch count. Sure, there might be a few frogged toes along the way, but that’s just part of the magic.
Before you go
Sometimes, you won’t have the chance to measure the feet of the person you're knitting for. In that case, here’s a quick reference guide to help you get started—assuming you’re using fingering-weight yarn and knitting in the round:
| Foot Size | Cast On (Approx.) |
|---|---|
| Child (S) | 48–52 stitches |
| Teen / Women's Small | 56–60 stitches |
| Women's Medium / Large | 60–64 stitches |
| Men's Medium | 64–68 stitches |
| Men's Large | 68–72 stitches |
Ready to Get Started?
Check out our sock yarns, stitch markers, and accessories here →
Treat your toes to something handmade—you deserve it!
