How to measure your knitting needles without a gauge

Seriously, I need a room for my yarn. My knitting projects, yarn stash and assorted implements are starting to take over. Today I officially decided that my knitting needle gauge is thoroughly lost. I have sort of thought that it might be lost for a few months now, but I’ve been in denial and as a substitute have just been measuring one needle against another. However, after tossing my bedroom tonight I’m convinced that it’s missing in action.

The reason this is a problem is because I’ve got a random set of vintage needles that cannot be categorized. They defy logic. They say they are one size, but many moons ago when I needed them for a project I discovered that they didn’t work because they were too fat. But they also don’t quite appear to be the next size up. They may, in fact, be something in between. I thought I could solve this problem by heading over to The Fiber Gypsy, which has a great comparison chart of all of the knitting needle sizes, past and present, but that didn’t work because the old, vintage size is supposedly the same as the new size. Ha.

So here I am, without a handy knitting gauge, and with a pair of needles that don’t match any damn thing. What’s a girl to do? Well, get back to basics, that’s what a girl does.

It occurred to me that every knitting needle has both random numbers assigned to it as a “size” as well as the actual millimeter size. Now, here in the U.S. we don’t pay much attention to millimeters, and even when we do, it might not occur to to us to actually think of those in terms of a physical ruler. But that little mm does have a connection!

Ok, here’s the deal. Knitting needles are measured by their diameter – that’s the width of a circle, or, to put it in more mathy terms, the diameter is the line segment that goes through the center of a circle, like so:

Parts of a Circle

So, to measure your knitting needles all you need is a ruler that has the metric system on one side of it and this handy dandy chart below. Simply measure the diameter of your needle by placing it between the hash marks on your ruler. Count how many lines it falls between. Remember that the metric system works in 10s. So one centimeter is equal to ten millimeters. Remember, this isn’t an exact science, especially once you get down to those pesky quarter millimeters, but it’ll do in a jiffy.

Craft Yarn Council, Yarn Standards Needle Chart

For me, those pesky needles measured 5 millimeters, meaning they are size 8s, or something darn close to it. Without my needle gauge it’ll be hard to tell if that’s correct, but for the moment I’m content with that assessment. Off to go cast on!

22 thoughts on “How to measure your knitting needles without a gauge

  1. Samantha

    OMG, thank you for this post! I have an unmarked set of needles that are too large for my needle gauge and upon deciding I could figure it out myself, got stumped when I measured the circumference and couldn’t make heads or tails of that number.

  2. Pingback: Knitting Needles

  3. Robin

    Thank you so much. I just found a beautiful set of unmarked wooden needles for $1.00 at the thrift store today & I had no clue how to figure out what size they were this was a big help.

  4. Wilma Duncan

    I have two sets of four double pointed needles. One is 4mm and the other 4.5 mm. Neither set is marked and it is difficult to tell them apart. I haven’t done any knitting for years and have lost my gauge. I hope this method will help to sort the problem.

  5. addy

    measuring the circumference is easier and more accurate, especially for the smaller sizes that are only a half mm or less different. it’s pretty hard to eyeball that.. but each mm you go up in diameter, the circumference goes up by about 3mm (pi mm, actually). just wrap a piece of paper around the needle, mark where it overlaps, and measure that!

  6. addy

    sorry, pi times diameter is circumference. it just so happens that for the diameter of the needles, each mm increase in diameter leads to an increase in circumference of somewhere around 3mm.

  7. Chris

    Very interesting needle gauge info. Thank you. Note to others. Check the gauge of your needles even if they are marked. I’m on swatch 3 for a garment I want to knit for my daughter and just got determined enough to find out why none of the sizes are matching up. Well, the recommended size (9) that I used for the first swatch turns out to be an (8) according to my trusty gauges. Yes I have two; one plastic and one aluminum that was gifted to me by a friend. I could easily fill a fair size room too. Just starting to reorganize and it’s taking two directions.
    1. Organize unfinished projects and finish them or dump them.
    2. Donate duplicate tools and excess (left over/remnant) yarns to the activities dept. at a local retirement home or after school program.

    Make a sincere effort to not increase my count of “wip”s
    Works In Progress!

    Good luck folks.

  8. Karen

    Thank you, from one who ONCE AGAIN misplaced my gauge. I had it only two days ago. Love finding alternate method. Now, I can rest assured, that going ahead measuring my gauge will show up.

  9. Dragon Lady

    Thank you, I am returning to knitting and have just been gifted my mother’s set of knitting needles, they are ancient, but have no markings on them at all. I can now size them, then I don’t need to make loads of test swatches.

  10. Lois

    I have run a hole through a piece of paper with the wooden needles we made at home and measured the width of the hole on the paper with a metric tape and they are approx. 13 cm across so I am guessing they are a size 17.

    1. Danyelle

      Oh, wow! Must be huge needles as 13cm is 5.12 inches, maybe you miss typed, if not I’d love to see these needles!😄

  11. Glynis Lailann

    I have been thinking along the same lines regarding needle sizes for some time. Thank you for confirming my theory on the subject.

  12. Allison

    I knit lace, so a lot of my needles are super tiny. I’m talking US 000. It’s pretty hard to see the difference visually, and most commercial gauges don’t go below US 0, so I made my own! Well, I modified my old Susan Bates metal gauge. If you can get a hold of a drill with small enough bits (which are measured in millimeters) you can do the same! Then I put a bit of nail polish on each one so I wouldn’t get them mixed up again.

  13. Beth French

    Thank you for the info on the wooden unmarked knitting needles. I have also found two unmarked crochet hooks. How does one measure those?

  14. Carol Horowitz

    Years later, this post continues to be of help! Unmarked circulars that I measured per your instructions and which were then pretty easy to identify as 4.5mm or US7’s. Thank you!!


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