The Problem
How many of us have a partial ball of yarn and don’t know how many yards it is?
OK, everyone put your hands down. Determining how many yards there are in a partial ball or mystery ball is one of knitting’s universal problems.
There are plenty of posts out there, covering a variety of ways to answer this question. So why would I write another one? Because I’ve taken a good hard look at every published method I could find, and here’s the dirty secret: none of them really work.
By that, I mostly mean they are inaccurate. There is no point to making an estimate of your yarn yardage if it has the potential to be wrong by 40%. As a former engineer — as well as a knitter who has been on the sad, losing end of yarn chicken* — that just plain offends me.
However, there are a few other considerations. A really good solution would have to meet four criteria:
- Good accuracy — because if you don’t get an accurate answer, what’s the point?
- Ease of use — this means low on time and effort, because if it takes an hour and you have to re-skein and/or re-wind a 500-yard ball of laceweight yarn, that’s a pain.
- Efficacy — it has to work over the whole range of yarn weights. And, it can’t rely on knowing what the yarn is. To be really useful, it has to work for any yarn that you know nothing about.
- Low cost – if it costs $100, well — that’s money that could be spent on YARN.
And, here’s the good news: I have a method that works. Simple, accurate, inexpensive, and works for any yarn.
If you want to cut to the chase and read about my method, find out what you need, and see some examples, click here.
Read on for the chatty version, including some history, all the available options, and in-depth explanation of the problems they present.
Background
Historically yarn has been sold by weight because it is easier to weigh a ball (or skein or hank) than to measure its actual length. Large-volume manufacturers are now required to include a measurement of length on the label (either yards or meters) but even a mass-manufactured yarn, if it’s vintage enough, may have been sold strictly by weight, not yardage.
In fact, this all started because yes, I had some bulky vintage wool yarn that was labeled only by weight, and I didn’t know the yardage. I was too lazy to re-skein it, and it was much too bulky for my fishing line meter. So, I went looking online for other methods I could use, with the vague idea of buying a McMorran Yarn Balance. As I searched, the realization grew that none of the methods available – including the ones I already had at my disposal — met my standards. I compared five published methods, and none of them met all four of my criteria.
Existing Methods
Comparison Chart
| RANK | METHOD | TECHNOLOGY | $ | ERROR RANGE | PROS | CONS |
| Fishing line meter | Direct measurement | $10 – 40 | Depending on tolerance of meter | Slow; extra yarn handling; limited to finer yarns | ||
| 2 | Niddy-noddy | Direct measurement | $5-$30 | Very good ~3% | Cheap; good accuracy; works on any yarn |
Slow; extra yarn handling |
| Yards per pound chart | WPI | free | Terrible ~20-40% | Quick and dirty; cheap | Wildly inaccurate | |
| 10-yard sample w kitchen scale | Weight | $10-15 | Poor ~20% | Quick | Inaccurate; need to cut large sample | |
| McMorran yarn balance | Weight | $35 | Unknown | Quick | Hard to find; accuracy unknown, more costly | |
| 1 | Digital gem scale | Weight | $25 | Excellent ~2% | Quick, easy, excellent accuracy, works on any yarn | none! |
Direct Measurement methods
Direct measurement methods tend to be a little more accurate than indirect ones — but with yarn, direct measurement is the whole problem: we are often dealing in hundreds of yards and measuring those directly is labor-intensive and time-consuming.
Fishing line meter: a lot of work and limited range
I own one, and it does sort of work, but I have not used it enough to vouch for its accuracy. Mine is a mechanical model (not digital), made mostly of plastic. It has never clamped securely onto my studio table, and at some point, the reset button broke. So it’s not a pleasure to use, but it does work.
The biggest con here, and the other reason I never used it much, is that you have to rewind the whole ball or skein and measure every inch of yarn. Having a ball winder makes this a little less painful, but there are also limits on that: your yarn must be fine enough to move freely through the meter. And remember these are made for fishing line. Mine works OK up to about worsted weight, but anything heavier doesn’t move smoothly enough. I tried to pull my bulky vintage wool yarn through by hand, but only for a few feet, until I realized that this was going to be a huge pain to do for the whole skein.
Finally, they don’t always measure in yards. So if you use this method, make sure you know whether yours measures in feet, yards, or meters.
Niddy-Noddy and Related Methods: accurate but a lot of work
The same con holds true for the less technical methods of using a niddy-noddy of known length, or winding onto a chair back, or measuring skein length, and counting wraps. Again, these methods work, and there is no limitation on yarn thickness — but if your yarn is already in a cake or ball, you end up re-skeining the entire thing, and then re-winding it into a cake in order to knit.
However, there are a couple of good things about the niddy-noddy method, which make it my favorite method out of the status quo. It is pretty darned accurate, and you can make a very serviceable niddy-noddy out of PVC pipe very cheaply. In fact, a PVC model is a little more convenient than a wooden one, because
- it’s collapsible for storage
- you can have interchangeable lengths for the middle bar to get different size skeins
- you can get it wet if you have a need to (spinners do this, I gather).
Here is how I measured the length of mine, using two tape measures held together with a couple of binder clips. One 60″ tape plus about another 16-3/8″ makes 76-3/8″ per wrap, or right about 2-1/8 yards (2.125 yards). If you don’t have two tape measures, you could loop a spare piece of yarn around your niddy-noddy, tie it or cut it, and measure its length.
I got very accurate results testing this method on one skein of my bulky yarn, once I figured out what it was (that detective work is discussed in Example 5 in the next post).
So: this is my second-choice method, partly for its accuracy; partly because it will work on any yarn; and partly because a lot of yarn is sold skeined anyway, so if you measure the length of the skein and count the number of wraps before you wind it and TAKE GOOD NOTES – problem solved. But if you lose that information or are working with a mystery ball to re-skein and re-wind, it still takes a lot of time and effort.
Also, I love the way this simple tool connects us to history. This painting by Leonardo da Vinci, which clearly depicts a niddy-noddy, is from about 1500. But another name for a niddy-noddy is a ‘yarn-cross’ in English, or ‘crois-iarna’ in Gaelic, and while I could not find a citation for how old either term was, I did find that the word ‘yarn’ exists in Old English – so since about 1000 or 1050 – and ‘skein’ is from the mid-14th century. And once a spinner had some yarn, they had to have something to wind that yarn onto, so I think it’s safe to say this simple yet effective low-tech tool has been around for much longer than 500 years.
Here’s the math:
Loop length (yards) x number of loops = yards in skein
Indirect Measurement methods
Here we introduce a very important concept: a conversion factor, or CF. This is the relationship between two measurements which allows you to convert one to the other.
This might sound complicated until you realize that weavers and machine knitters have been using a conversion factor to get yarn length for a long time: yards per pound, or YPP.
Here’s the math:
weight of yarn (pounds) x yards per pound = yards of yarn
So. How do you find an accurate conversion factor?
The answer is by measuring both weight and length on the same piece of yarn — which isn’t always as easy as it might sound.
One way is to define that “piece” of yarn as a full ball, and if you know what the yarn is, you can use label information or Ravelry to get both its length and its weight.
But if you don’t know what yarn it is, you’re stuck. Also, even a few modern yarns don’t include both weight and length information on the label: for example, Tosh DK only gives yardage, not weight.
Read on for a look at a few ways that fiber folks have approached the problem of finding this conversion factor.
WPI to YPP chart: wildly inaccurate
The most popular published “solution” is to use WPI to take a guess at yards per pound. Which is… not useful.
The chart below is partially reproduced from an article on Interweave’s website – but they are by no means the only source for this nonsense. In a nutshell, you measure the wraps per inch of your yarn, and from that you get a very wide range for YPP. Then you weigh how much yarn you have and multiply that by YPP to get a very wide range of yards.
| Yarn Category | Wraps per Inch (WPI) | Yards per Pound (YPP) | Error Range | Ravelry Sampling of WPI and YPP |
| Lace | 18+ | 2600+ | infinite, apparently | Lace 2600-4000 |
| Fingering | 16 | 1900-2400 | 24% | |
| Sport | 14 | 1200-1800 | 42% | Fingering (14) 1200-2000 |
| Worsted | 12 | 900-1200 | 29% | Worsted (9) 750-1200 |
| Bulky | 10 | 600-800 | 29% | |
| Very Bulky | 8 or fewer | 400-500 | 23% | Aran (8) 750-1000 |
There are so many problems with this method I don’t even know where to start.
Big Problem: WPI is a measurement of how WIDE a strand of yarn is. You can’t use the yarn width to define a relationship between its weight and length because those are three completely different measurements!
Bigger Problem: As a measurement technique, WPI has consistency issues. Even the yarn industry can’t agree with itself on WPI. WPI has a LOT of variation built into it, not only from the fact that it all depends on just how tightly you wrap the yarn, but also how springy or stretchy the yarn itself is. This results in Ravelry saying that worsted weight yarn is 9 WPI, while the Interweave chart calls that somewhere between bulky and super-bulky. I think we can all agree those are two very different yarns.
Biggest Problem: That wide range they give for YPP. That is because this one chart is trying to do the job for all fibers: cotton, wool, acrylic, and so on – and different fibers have very different YPP for the same thickness of yarn.
Interweave proves that in its own Master Yarn Chart, where
- 8/2 linen = 1200 YPP
- 8/2 silk = 2800 YPP
- 8/2 acrylic = 3000 YPP
- 8/2 cotton = 3360 YPP
- 8/2 rayon = 3360 YPP
So five different fibers, all the same width (8/2) but nearly 3x the YPP between linen and cotton or rayon!
The worst case in the knitting yarn chart is sport weight, where you can have anywhere from 1200-1800 YPP. This is a range of error of over 40%. FORTY PERCENT.
So if you had ¼ pound (4 ounces) of sport weight yarn, you could have anywhere from 300 yards to 450. (Although if you want to make something that takes only 200 yards, I suppose that might be useful information, if you can trust it. I don’t.)
I have added a column for error range to the chart above, where you can see that even the best range is over 20% potential error! That is an awful lot of yarn to be short of.
Weighing A 10 Yard Sample: sort of easy, but inaccurate, with limited range
A digital kitchen scale is great for weighing balls of yarn at 50 or 100 grams, but it doesn’t work at all to weigh a yard of yarn, which weighs less than a gram. Much less, in many cases — at least until you are in super-bulky or jumbo territory.
One often-suggested way to get around this is to increase your sample size: measure off multiple yards of yarn, say, 5 or 10 yards, and weigh that. But there are problems here, too.
One is, it still isn’t all that accurate. Most kitchen scales weigh down to the nearest gram, which means any measurement can be off by half a gram. For example, if your item really weighs 2.5 grams, your scale will show you either 2 grams or 3 grams. And if you can be off by half a gram on a 5-gram sample, that’s still an error range of 20%. (On a 50-gram ball of yarn, that same half a gram is only a 2% error.)
The other lies in how much yarn you actually need in order to get into that 5-gram territory. For worsted or aran weights, it’s 8-10 yards. But go lighter, and you need a lot more yarn: for fingering it’s 15-20 yards; for laceweight, it’s 40-50 yards!
Here’s the math:
sample length (yards) / sample weight (g) x weight of ball (g) = yards in ball
The McMorran Yarn Balance: if you have one
This device turns the problem around, and instead of weight it measures length: specifically, how long a piece of yarn it takes to weigh 1/3600th of a pound. It has been used by spinners and weavers for a long time, but I’ve never personally used one.
You hang a piece of yarn on it and snip away at it until the balance arm shifts, which means the possibilities for error include how much you snip at a time, and your measurement of how long the piece is. I couldn’t find any information about how accurate it is likely to be, which probably varies with the manufacturer anyway.
It’s also tough to buy one. I couldn’t actually find one for sale, but it appears the price was $35-$40. I did find an Interweave article on how to make one, but I have some serious doubts about the ability of a home-made balance to accurately weigh a fraction of a gram.
Phew. All that and still nothing that works well.
In the next post, I’ll show you the way that works!