Sock Knitting 101: How a Sock is Supposed to Fit | Interweave (2024)

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I am so disappointed when I knit something that doesn’t fit. Aren’t you? There are some patterns where you don’t have to worry about fit a lot, such as scarves and cowls, but most patterns need a little thought about how they will fit the recipient. Sock knitting is included in that category. Although you may think you need to know just the length of the feet of the person you’re knitting for, you would be wrong. Sorry. Kate Atherley, author of, Custom Socks: Knit to Fit Your Feet, and stars in the video workshop, Knit Socks that Fit, is here to talk in-depth about sock knitting and fitting, and the measurements you’ll need to make them perfect every time.

Here’s Kate to tell you more about knitting socks that fit.

How a Sock is Supposed to Fit

Yes, it’s true! We’re releasing a whole book on the topic of sock fit. (It’s not just about how to fit a sock, but the book also provides lots of great patterns and tips on how to customize a sock knitting pattern for special fit needs.) Sock fit matters for two reasons: comfort and longevity. If you’re going to go to the trouble of knitting a pair of socks, they should fit you properly. A well-fitted sock is more comfortable to wear and will last much longer. Socks should be worn with a little bit of negative ease—that is, they should be smaller than the foot (and leg) they’re to cover. You want the sock to have to stretch a bit so that it will stay up on your leg and stay in place on your foot. A common problem cited with handknitted socks is that the legs don’t stay up—in many cases, this is simply because the sock is too big.

A handknitted sock (especially one made out of wool or other animal fibers) will stretch out over the day. Unless the sock stretches somewhat to fit your foot, this added stretch can cause the sock to become floppy as the day wears on. In addition to feeling uncomfortable, loose floppy socks will move around inside shoes and wear out much quicker due to the added friction. A sock that has to stretch to fit your foot will stay put, feel comfortable, and resist abrasion.

For the best fit, a sock for an adult should measure about 10 percent—practically speaking, that corresponds to about 1” (2.5 cm)—smaller than the actual leg or foot circumference, and about 1/2” (1.3 cm) shorter than the actual foot length. A sock for a child should also measure about 10% smaller in circumference—about 1/2” (1.3 cm) for a foot with a 5” (12.5 cm) circumference—and about 1/4” to 1/2″ (6 mm to 1.3 cm) shorter in length.

If you haven’t been choosing your sock size based on these rules, chances are that you haven’t enjoyed well-fitting socks. Follow these guidelines for your next pair of socks and you’ll find an instant improvement in fit, even if you’re following a standard sock knitting pattern.

How Sock Knitting Patterns Are Sized

The finished size of the majority of sock patterns—whether they’re knitted toe-up or top-down—is based on the foot or ankle circumference. This makes sense—the socks have to fit around the foot and ankle, whereas the foot length and the leg length can be easily adjusted by working more or fewer rounds. When we talk about foot circumference, we mean the measurement taken around the ball of the foot, which is typically the largest circumference, discounting any bunions. You don’t want to include a bunion in this measurement because that bony protuberance typically occupies less than 1″ (2.5 cm), or 10 percent, of the foot circumference or foot length. The inherent stretch in knitted fabric will accommodate this amount of variation.

If you based the sock size on that larger circumference, the sock would be too big for 90 percent of your foot. This is why it’s good to be a knitter—we make a fabric that stretches. A sock with 10 percent negative ease will still stretch to fit comfortably around an area that’s a bit larger. When we talk about ankle circumference, we mean the measurement around the narrowest part of your ankle—usually just above those characteristic rounded bones.

Most sock patterns assume that the wearer’s foot circumference and ankle circumference are the same. (Note that some sock patterns call this measurement the “leg circumference”—it’s because for the majority of calf-length sock patterns, the circumference of the sock leg is constant from top of cuff to the top of the heel, so either term works.) So, assuming your foot confirms to this standard, you can base your size on either measurement. But, remember that you want to allow for negative ease, so the finished size that you want to follow should be 10 percent—that’s about 1” (2.5 cm) for an adult sock—smaller than your actual foot or ankle circumference.

Not all sock patterns provide the same sizing information. Ideally, you want to know the “finished” measurements or “actual size” of the sock. This will tell you exactly what to expect in the knitted sock. Sizes that are described as “to fit” or “foot size” describe the foot intended to wear the sock, not the actual sock measurements. Unless you know exactly how much (if any) negative ease is allowed, these measurements won’t tell you the actual size of the finished sock.

If the sock sizes are given as ankle or foot circumference:

Choose a size that has about 10 percent negative ease—about 1” (2.5 cm) for an “average” adult sock; about 1/2″ to 1/4″ (6 mm to 1.3 cm) for an “average” child’s sock.

If the sock sizes are given as shoe sizes:

First, check where the pattern was published—shoe sizes differ regionally and a U.S. size 7 shoe is different than a UK size 7 shoe. In general, shoes are designed with the expectation that a longer foot (larger shoe size) corresponds to a larger foot circumference and shoe sizes assume that the foot has an “average” or medium width. If your foot is narrow, you’ll probably find the socks too big; if your foot is wide, you’ll probably find the socks too small.

The only way to know for sure what the finished sock will measure around the foot or leg is to divide the number of stitches in the foot or leg by the number of stitches per inch in the stitch pattern used (assuming the stitch gauge for the pattern used on the foot or leg is provided). For example, if the pattern calls for 68 stitches in the foot or leg and the gauge is 8 stitches per inch (2.5 cm), the finished sock will measure about 8” (20.5 cm) in circumference.

68 stitches ÷ 8 stitches/inch = 8.5″

If the sock sizes are given as foot length:

Be careful. The typical assumption is that foot circumference increases proportionally with foot length. But the relationship isn’t this simple. If the pattern doesn’t include the finished foot or leg circumference, you’ll want to calculate it yourself based on the number of stitches and the gauge. If you can’t find (or calculate) the finished measurement, these patterns are best avoided.

If the sock sizes are given as standard names, “small,” “medium,” “large”:

Again, be careful—if there’s no indication of the actual size, you can’t be sure of what you’ll get unless you can calculate the finished measurement from the stitch count and gauge.

If the sock only has one size:

Beware—one size does not fit all! Unless the finished measurement is also given, there’s no way to know how it will fit unless there’s enough information for you to calculate the finished measurement yourself. All of this is to say that you need to know your measurements and the finished measurements of the sock—foot and leg circumference and foot and leg lengths—to know if a knitted sock is going to fit.

—Kate Atherley

This info is so helpful. I don’t knit a lot of socks, and part of the reason why is that they haven’t fit me properly. They are either too tight on the calf or I have to really tug them over my heel to get them on. So I choose my store-bought socks over my handknits, which is super sad, right?

Kate is a sock knitting superstar, and her new resources are must-haves if you’re a sock knitter or you want to become one. Start knitting socks that fit with Kate! Her wonderful video workshop, Knit Socks that Fit: Create Patterns Using Precise Measurements and Gauge, is available as a video download.

I know I’ll be using these references and patterns. Here’s to socks that fit!

Cheers,

Kathleen

Originally posted on July 15, 2015; updated on March 28, 2022.

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