How Much Yarn for a Long Tail Cast On

How Much Yarn for a Long Tail Cast On? Find Out Here!

Hello, Makers! Today I'm back with a two vastly different "tricks" on estimating yarn for cast ons. I'm giving you mine, which I hope makes you giggle, and then a far more accurate tip/trick I learned from a former student of mine.

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This amazing woman has been knitting for more decades than I've been alive and while I'm always honored to teach knitter something new, I'm even MORE invigorated when a veteran knitter is willing to teach me something. So heres little ol' me, passing on decades of information to you! 

When I first started learning to knit via booklets available at local craft stores, the most common cast on was the Knitted Cast On. The Knitted Cast On is a short tail cast on method where by a slip knot is created just 6"/15cm (or so) from the end of the working yarn, and stitches are knit onto the needle. 

Nowadays (close to 20 years later.. really?! Jeez... yep, really... almost 20 years) the most common cast on is the Long Tail Cast On method, or some iteration of a long tail method, such as the German Twisted Cast On or the Long Tail Tubular Cast On

The biggest "gotcha" of any long tail cast on method is estimating how much yarn you need to wind off before placing your slip knot (or creating your first stitch if you don't prefer to start a cast on with a slip knot). I hope you'll add one (or both) of the following two methods to your bag'o'tricks for future projects. 

Arm Span = 80 Stitches

Admittedly, this is MY tried and true method. It rarely fails me but it's definitely not particularly accurate. 

The rule of thumb I was taught with this method was this:

For the average woman, one full arm span from hand to hand (imagine you're standing like the Anatomical Man with your arms spread wide, side to side, with the tail end of the yarn in one hand and the working end in the other) of worsted weight yarn is 80 stitches.

Already I know you can see the flaw in this method. Or should I saw flaws, plural. 

1) The arm span of someone like me (I stand at a whopping 5' 3" tall) is vastly different than that of my best friend who is 5' 11". If you're curious, she refers to me as someone with T-Rex arms from time to time. 

T-Rex Sweater

This image is VIA; we take no credit for the amazing-ness that is this mini sweater!

2) What about when I use OTHER weights of yarn?  

I do promise that unless you are truly proportioned like our friend the T-Rex here, that an arm span really does work to cast on 80 stitches using the traditional long tail method. If I'm casting on using the German Twisted Cast On method, I add about 4" / 10 cm of yarn extra since that method takes up a bit more yarn per stitch. 

From this point, I tend to make an educated guess on how much yarn I need to wind off for a long tail cast on. For example, if I'm knitting a sweater and I need to cast on 120 stitches, I know that 80 stitches is one arm span, so presumably an additional 40 stitches is the distance from one hand held to the side, to the center of my body, directly below my chin. This, of course, really only applies when working with a worsted weight (maybe a DK weight) yarn. 

Other pieces of anatomy to cast on by! 

I have had some fun sorting out other parts of my body I can use for projects that I knit regularly. Because I love knitting socks and don't love taking a lot of tools with me when I do, I've discovered two lengths of yarn that have not failed me when casting on for socks. 

To cast on toe-up socks: the distance between my wrist and my elbow pit (is that what you call it? the inner elbow?) is the perfect length to cast on the small amount of stitches needed at the toe of a sock. 

To cast on cuff-down socks: one arm length, from my fingers to the top of my shoulder, is a great length to wind off to cast on for the top / cuff of a sock.

A More Measured Approach - Wrapping Your Needle

I think this is the method of estimating yarn that will resonate with more knitters facing a long tail cast on yardage conundrum. It's a bit more accurate and doesn't use your varied anatomy lengths to estimate. 

How Much Yarn for a Long Tail Cast On

This method, handed down to me from my beloved friend and knitter extraordinaire, is pretty basic. And she swears by it. 

1) Using the project needle (i.e.: if you're casting on Sport weight yarn onto a US 6/ 4mm needle, use the US 6 / 4mm needle for the wrapping), wrap the yarn around the needle 10 times. I promise there are 10 wraps on this needle, one is just tucked away under my thumb because taking a picture of your own hand holding yarn wrapped around a needle is trickier than it sounds.

2) Mark the length of yarn you're using either by pinching the yarn or even putting a little twist tie on it to denote the length closest to the tip of the needle at the 10th wrap. This is the yarn needed to cast on approximately 10 stitches. 

3) Math out how much yarn you'll need for the number of stitches you have to cast on. For example, if you needed 4" / 10 cm to cast on 10 stitches based on this wrapping method, and you need to cast on 96 stitches (a very common number for a hat) you can divide 96 stitches by 10 stitches (the number over which the length was measured) and you'll get 9.6. Then multiply this 9.6 by 4" / 10 cm to get a target length of 38.4" / 97.5 cm. 

4) Jan (that's my dear friend) also says "add just a little bit more". She's never confirmed how much that "just a little bit" is but as I've watched her do this I would say she adds about 4" to whatever her target length is from Step 3. 

Jan has never NOT made a cast on using this method so if you're ever unsure, I say give it a try! 

How do YOU estimate yardages? 

I'm still giggling a bit over my find of the perfect T-Rex in a sweater picture, above. I do have pretty short arms, which really does poke a lot of holes in the anatomical estimating theory. What is YOUR favorite method of estimating yarn to wind off for long tail cast on methods? Is yours a bit more customized to you and your body, like mine, or do you take a more mathematical approach like Jan?