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Substituting yarn for a project can be just like the game Mystery Date. Will it be a dream (sigh) or a dud (groan)?

The gauge can be right, and it can look fine, but sometimes there’s just something that makes a substitution fail in the end. 

The reason for this not-quite-rightness may lie in a something that spinners call grist.

Grist is the density of a yarn; the concept factors in both the circumference and weight in a length of yarn. Spinners and weavers talk about grist with the acronym YPP or yards per pound.

It’s kind of a gross word, calling to mind gristle, but once I started paying attention to grist, I became much happier with my yarn subs.

Grist is key to the hand and heft of a finished project. Knowing the grist of a substituted yarn can help you avoid running out, and (my favorite) it can also keep you from making a 12-pound sweater coat. In addition, knowing how to measure grist will give you the power of knowing the yardage in every skein in your stash that is missing its ballband.

What affects grist? All the things I’ve talked about in past posts: the type of fiber in your yarn, whether it is woolen- or worsted-spun, and the number of plies in the yarn.

Spinners and weavers figure out the grist of a yarn by measuring and math. Knitters have it easy: all the info is right there on the ballband, no measuring needed. When I work with knitting yarns, I check my grist with yards per ounce.

All you need to know is how many yards are in an ounce of your yarn. It may just save your knitting day.

Mystery Date Contestant Number One

I have a knitter friend who told me she often runs out of yarn when she subs. I asked about her subbing process. She says she uses a similar weight yarn, swatches, and then subs by weight (I know, bless her heart).  Here’s an example of where she was heading into yarn sub dud date territory, but we saved her by checking her grist.

My friend wants to knit a shawl that calls for a skein of Sincere Sheep Cormo Fingering with same weight of Koigu that she had in ancient stash. Both yarns are fingering weight, and knit to the same gauge.

Left: Koigu, our mystery date contestant. Right: Sincere Sheep Cormo Fingering.

Here’s what the labels say:

Sincere Sheep Cormo Fingering: 500 yards, 4 ounces (color: St. Barts).
Koigu Premium Painter’s Palette (100% Merino): 175 yards, 1.76 ounces.  (My friend has 2 skeins and a little more, adding up to 4 ounces.)

We know that the Sincere Sheep is 500 yards per 4 ounces (or 125 yards an ounce), so that’s the number the Koigu has to hit for it to be a dreamy sub for the Sincere Sheep.

The Koigu has 175 yards in 1.76 ounces:  99 yards per ounce, or 396 yards in 4 ounces.

Girl, that date is a dud! If friend substitutes 4 ounces of the Koigu for 4 ounces of the Sincere Sheep, she’ll only get three-quarters of the way through the shawl before she runs out of yarn.

If you want to know a big reason why the Koigu is a denser yarn (it has fewer yards per ounce), look closely at the ply twist in the two yarns. The Sincere sheep has a very light ply twist, and the Koigu has a tighter twist. The tighter twist squeezes more fiber into the measurement of yarn, so it’s heavier and has fewer yards per ounce.

Mystery Date Contestant Number Two

The next story is my own tale of woe.

I fell in love with Independence Wool’s Texas Tweed and I decided I wanted to knit a sweater out of it. I found a sweater pattern that calls for 1,600 yards of Sincere Sheep Cormo Sport.

On the LEFT: Sincere Sheep Cormo Sport. On the RIGHT: our Mystery Date, the handsome Texas Tweed.

I swatched my Texas love and it worked as a sub. I knew I would need 11+ skeins of Texas Tweed to get the yardage.

Here are the label stats:

Sincere Sheep Cormo Sport (100% Cormo): 400 yards, 4 oz (color Vitamin C).
Independence Wool, Texas Tweed (60% Rambouillet/40% Mohair): 140 yards, 2.25 ounces.

I paused and did some math. The Sincere Sheep sweater weighs just a pound, which is great for my chosen size. But the Texas Tweed? 11.5 skeins (1,600-ish yards) weigh 1.7 pounds, almost twice the weight.

No, thanks. My Texas Tweed will probably become a shawl.

The why of the extra density in the Texas Tweed is in the fiber. The Cormo in the Sincere Sheep is very fine and light. The Rambouillet in the Texas Tweed is also fine and light, but the mohair, although gorgeously shiny and slick, is a strong and heavy fiber. The mohair is what tips the scale.

In the MDK Shop

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By Julia Hilbrandt

The Truly Mysterious Mystery Date

What if you have yarn without a ball band, or leftover yarn with long-forgotten statistics, and want to know the yardage?

Step aside: measuring grist will reveal all!

When measuring for grist, you need to know the weight of a specific length of the yarn.

tangled up in pink. Misunderstood Mystery Date on the left. Measured length of mystery yarn on the right.

I use a digital scale and 10 yards of yarn. I weigh it in ounces. I divide the yardage by the weight, and presto: I have the number of yards in one ounce of that yarn.

I have a mystery tangle of yarn (which I think is cashmere, btw) that weighs .055 ounces for 10 yards.

10 divided by .055 is 181.8 . The grist for my mystery yarn is 181.8 yards per ounce.

My sexy yarn pile weighs .55 ounces, so I have 99.9 yards of it. (181.8 x .55).

Taking the time to check your yarn’s grist as part of the substitution process is quick, and can save you the heartbreak of a dud.

May all your yarn substitutions be a dream.


This Could Come in Handy

This post may be the Clip & Save of all Clip & Saves! Be sure to save it someplace where you can find it the next time you embark on a yarn substitution.
Here’s how to save this article in your MDK account with one click.

About The Author

Jillian Moreno spins, knits and weaves just so she can touch all of the fibers. She wrote the book Yarnitecture: A Knitter’s Guide to Spinning: Building Exactly the Yarn You Want so she could use all of the fiber words. Keep up with her exploits at


  • Thank you. I have been knitting for over 50 years and have never heard about “grist”. It makes so much sense. Have saved and pinned the post for future reference,

  • Brilliant article—I used to work in my LYS, and I wish I had had this article when I was trying to explain to my co-workers why you can’t knit everything out of Cascade 220 even if you can find a needle size that will give you gauge!

    • This article and this particular comment have just helped me avoid a biiiig mistake! 🙂

  • Brilliant thank you!

  • Mystery Date! We spent hours opening and closing that door, though I don’t remember ever playing the game as intended.

    • Haha – Same here! I recall the photos of the dates as a bit different – maybe we had a different edition. Did you also have a Campus Queen lunchbox?

      • Is that the game with Pointdexter?;)

  • Super helpful. Thank you. I am saving this one!

  • What a great article! Thank you so much the information will help me so much,

  • Jillian! You are my new hero! Thank you for supplying another piece to the yarn puzzle. Also, I have figured out that if my LYS owner is also a spinner I will get better answers.

  • I do this all the time but had no idea there was a word for it! Thanks! Now that I’ve learned something new, I wonder if I can call it a day and head home? (It’s not even 8am yet but I checked, just in case. Boss laughed. Back to work,)

  • Wow. Never heard of grist. This information is extremely useful since we all sub yarns all the time!

  • Thank you so very much for all that wonderful,useful info AND how to save the article. My little sister had the Mystery Date game – what a hoot to see that corny commercial again!

  • My mind has been blown. I never even thought that yarn substitution would affect the weight of the finished project (other than woolen v. worsted spun). Wow! Saving article!

  • This was so helpful. I feel like I have a place to start from with my stash and substitutions. I appreciate the article and visuals. thank you

  • Whoa! Clicked and saved! Thank you so much for this.

  • WOW! That’s all I can say!

  • Thank you!!! Just another piece of the puzzle I have been needing. So much to learn, so little time.

    • Thank you!! I tried a mystery date yarn for socks this week and thought about Paul Bunyan after getting to the gusset!!! New project in the future and will be checking grist!

  • Thank you! This information is so very helpful!

  • This is so very helpful! My co-worker just recently came to me with two rolled balls of yarn (both 4-ply) without tags and asked if she could make a shawl with it. She doesn’t know the name of the yarn or anything other than she has 2 balls of yarn. I knew I would need to do something like this, but you took all the guess-work and fuss out of it and I’m actually excited to figure out the mystery yarn and will make it a dream mystery date for my co-worker!

  • Great info! I knew a little about finding the yardage for mystery yarns, but I never thought about the weight of the project . Something really good to consider!

  • Thank you for this very helpful information!! I knew that there must be some formula that would take away the ambiguity when substituting yarn. I have some lovely hand spun and dyed yarn that is neither here nor there; fingering, lace, ‘flace’ who knows? This will help enormously. Math saves everything.

  • Such helpful information, thank you!

  • Wow. I’m working on something with a substitute and eating up yarn too quick. Now I may know why!

  • Wow. I hope my mystery date of a cardigan turns out!!! I could do the math, but don’t want to look behind door #1 to find out. Lol.

  • Wow, who knew ? Thanks !

  • Thank you for the sound advice. Going to a friend’s house to have Knitting Day. Will bring along this article to share. So wise!!!

  • That looks like a great scale, mine definitely is not accurate to .001 ounces! What brand is it?

  • Instead of thinking of gristle – think of grist mill, used for grinding grain for meal or flour.

    Thanks for the information.

    • Exactly my thought. “Grist for the mill” to me means that it’s raw material (a dream, thoughts) that might be useful sometime.

  • I have never heard of yarn ‘grist’, but after too many years of hit-or-miss yarn subs (‘the swatch looks great, they’re both listed as fingering, it must work’), it dawned on me recently that weight of yarn had to be factored into a sub. (A ‘DUH’ moment. But a happy one, which saved my most recent sweater.)
    Even still, I hadn’t considered the weight of the finished project and I will want to calculate that too, if I don’t want to end up with a 12 pound sweater – which would be a dud date for sure. Another ‘DUH’ moment! Thank you!

  • Thank you!
    And thank you for showing how to save this article!
    Mystery Date, my sisters and I had tons of fun playing that game! Which is weird considering the diverse neighborhood I grew up in!

  • Such a great, useful article but…math are hard!!! And I don’t own a scale so I guess I’ll continue to play Mystery Date with my yarn subs 🙂 I will save the article, maybe my brain will engage after another cup of coffee

    • Scales are super cheap on Amazon. Mine was under $10 with free shipping and I’m very happy with it . Brand is Ozeri

    • “Math are hard” oh the giggles you supplied with that phase!! Thanks I needed that!!

    • Check thrift shops for digital kitchen scales – very often under $10

  • Thank you!! Today I learned the difference between worsted-spun and woolen-spun yarns AND about grist. New knowledge to set me on the right path!

    • It is so sad to see that knitting classes no longer teach all the essentials, like they once did. How are new knitters going to know all this when they are not being taught it?? I feel so sorry for the next generation!! They will never survive!

  • This is going to be super helpful with my oft-repeated (and occasionally followed) promise to knit from stash instead of buying new yarn for a project. I’m not quite at the “don’t buy green bananas” stage yet, but knitting from stash isn’t far behind.

    • I am right there with you, Judy!

  • thank you! very helpful info with useful examples.

  • Thank you so so much for your fantastic article. I crochet and am constantly subbing yarns. I usually just change up the hook size but your article sheds a whole new light on things. Thanks again.

  • Wow. Thank you! This info is going to help me so much (says someone who knit a REALLY HEAVY shawl last year).

  • I’ve used the expression “grist for the mill” my whole life, and frequently, and never once thought of associating “grist” with “gristle.” Yuck.
    That said…this is a fully-packed useful post, and I will read it multiple times, I’m sure! Thanks very much 🙂

  • Grist is just a complicated way of saying that when you substitute yarn you look for a one that knits to close to the same suggested gauge, is a fiber with similar properties, & has approximately the same yardage/ounce or gram as the yarn used in the original pattern. Takes a teensy bit of math if the two yarns aren’t in the same size put up, but most of the time you don’t even need a calculator.

  • Thank you for this wonderful explanation! I have knitted since God created sheep and love to substitute yarns out of my stash or from falling in love with a different yarn in a shop. Over the years I have come up with the concept of “not quite right-ness” of one yarn for another and therefore moving on to a different. one The factors included weight, tightness of ply or density, how it felt and looked in comparison to the original but I didn’t have a word for it. Now I do: GRIST. I can hardly wait to use it.

  • Wow…so helpful! Thank you.

  • I make dolls and other children’s toy pets . Would the product be good for these items

  • Brilliant post! Thank you!

  • This is life altering, thank you!

  • Thank you too much for this explanation. I’ll be sure to use the info when subbing yarns from other countries (inherited).

  • Thank you, thank you, thank you…funny that I had just noticed YPP recently and wondered what it meant!

  • Wow, thanks. Very informative. BTW, I loved the Mystery Date video!

  • I worked in a yarn store back in the – ahem – 80s, and we never would’ve swapped yarn out any other way. The term “grist”, though, is new to me.

  • Thanks for the great (re)statement and definition of grist. I had done this for awhile, after few really dud dates (cotton?), but you helped me to understand grist at SAFF. Good to have the information renewed.

  • Wow! Great info. I have numerous balls of yarn which I have weighed and label but I have on idea of how many yards I have. Any secret to find out without unwinding and measuring?

    • Take a look at Jillian’s last section above, with the pink tangle of yarn. She measured out 10 yards of it, weighed it, and from those 2 data points she was able to calculate how many yards were in the tangle.

  • Great article! I’m debating what to do with my unfinished shawl made with a substitute yarn … do I rip back and add stripes to make it not look like I ran out of yarn or try to find a colour match for 5 year old stash yarn? I’m saving this article article and going to use it for all future projects.

    • I love this striping strategy. It has the bonus of being a fun way to communicate with other knitters without words. They will see the stripes and know the score! Seriously though, I’ve seen it work really successfully.

      • Thanks Kay! Stripes it is!!

  • Another for my very long list entitled ” Helpful Things I Have learned from Ann & Kay” . Along with the concept, what a great name for it. GRIST!

  • Gosh, this is how I’ve always subbed yarn, but I didn’t know it had a name! In fact, I wasn’t even sure if it was considered a legitimate way to find a suitable sub – I just knew that it had always worked for me. I feel so smart now!

  • So helpful! Cheers!

  • Thank you, thank you!!

  • This was brilliant – the “girl, that date is a dud” is hilarious. I will definitely be using this math today to estimate yardage on a 1/4 skein I have. But I have a question about date #1. Why can’t she just compare the yardage and see that she will be short yardage for the project? I see how it works for date #2 and date #3 but not sure what extra it revealed for date 1 when the yardage, yarn type and gauge was known.

  • Thank you so much for this post! I had mystery yarn from Value Villige, The look and feel of yarn plus the Grist measurements, burn test, WPI, and guage swatch, etc. I have been able to figure out that it is most likely 100% fingering weight cotton with grist of 3.33 yards per gram equalling a total of 4,155.84 yards

  • Then, there’s the McMorran balance, an extremely clever, useful, and fun-to-play-with tool for measuring ypp. Maybe grist for a future article?

  • Brilliant! Thank you.

  • Hi Jillian. This is a fabulous resource for knitters. Thanks so much for sharing. I’ve included your post in our latest craft inspiration roundup. Cheers Jodie 🙂

  • Thank you for sharing such GREAT INFO!!

  • Huh. Who knew? That answers a lot of questions. Thank you!

  • Thank you so much! I have sweater quantities of a gorgeous Rowan tweed from the 90’s. But how much exactly? Now I can find out!

  • This article was so informative, thank you so much! This opens up a whole new world for me.

  • I’ve been married and divorced twice. I always like to look back on different phases of my life and think of something positive and useful that I learned from them.

    From my first ex-husband I learned not to marry philandering jerks. In retrospect I wish that I hadn’t narrowed that down to one specific category of jerks.

    From my second ex-husband (an entirely different sort of jerk from the first one) who spent his career in marine shipping logistics, I learned the lesson of grist. In the days of sailing ships carrying cargo around the world, it was very important that they used the right gauge ropes in the rigging and this is exactly how they checked – using a balance scale as opposed to a little digital kitchen scale. At the time I learned this lesson about 25 years ago, I bought a little McMorran balance scale which I’ve used many times on mystery yarns and have had some lovely knitting dates.

    As they’ve been saying for a very long time, since the book of Ecclesiastes in the Old Testament of the Bible, there’s very little new under the sun.

    PS: From my two marriages I learned that I’m very bad at choosing husbands and that I’d be far better off living with my wonderful yarn stash that I built up for my retirement, and a cat. I’m delighted to say that I finally got it right. My cat, my stash and I are loving every moment of my retirement.

    • Sweet!

  • I’m printing this article and filing it, so I remember I have it and can refer to it immediately! Thank you for the insights and methods to substitute with aplomb!

  • “You are my density!”

    “Grist” reminds me of “grift,” which might be appropriate if you’re trying to get away with substituting a yarn without enough substance. Don’t become a grifter by messing with the grist!

  • This was so helpful in understanding why some yarns are problematic when substituting for others in a pattern. You made my day!!

  • I seem to have issues with Pilling. Is this the way I knit or is this the yarn?

  • This article gives the right way to use grist information. I once used it the wrong way: I was planning to knit Timpani, a beautiful jacket by Connie Chang Chinchio, with sideways cables that looks a little like a band uniform. I thought that the designer’s yarn choice, Green Mountain Spinnery Cotton Comfort, must actually be a sport weight rather than the DK weight it claimed to be, because its grist (180 yards / 57 grams) was more in line with a typical sport weight. So I substituted a sport weight yarn with roughly the same grist. That resulted in the jacket being a wee bit tight, although still wearable and very chic. I’ve since learned to spin and understand that grist doesn’t line up exactly with yarn class, because of the difference between woolen spun yarns and worsted spun yarns. Woolen spun yarns are airier and can appear (and knit up) as thicker than their grist would suggest.
    Another caveat: cotton is heavier than wool, and comparing yarn class and grist between cotton, cotton blend and wool yarns can be confusing.

    • lol and here i was, trying to compare woolen and cotton worsted to see if i could use the cotton organic on a baby cardigan. i knew it was heavier, thus all the math. i think i’ll search out a different organic worsted appropriate for spring.

    • I agree!

  • Well … THIS explains a lot! Just checked the grist on my current project. Wrong!!! I kept having this niggling suspicion that the project wasn’t going to come out as hoped. I was right. Now to go pull out 800 yards of yarn. {heavy sigh}

  • Sorry I am late to this party. Question: is there an easy way to measure the yardage of a mystery yarn in order to determine its grist?

  • Thanks so much for your explanation of yarn subscriptions. Now I can sub with confidence.

  • So what about subs for a garment that calls for 2 different yarns held together??

  • Thank you so much for this article! I can’t tell you how many times I have found a pattern and hated the yarn choice! I buy yarns that I like the feel of. Not Acrylic yarn which works for holiday or amurgumi (spelling? Lol) items.

  • Hi Jillian. I am a relatively new crochet enthusiast. I live in the Philippines where good source of yarn is hard to find and imported ones can be expensive. Also, some patterns I want to use (like shrugs and tops) call for worsted weight yarn. This type of yarn is too hot to wear here. How would I substitute worsted weight yarn or even bulky yarn for lighter types like bamboo cotton? How much yarn will I need?

    Hope you can help me with this. Many thanks in advance.

  • Such a great article! I’ve been applying the principle of grist intuitively with slightly better than fair rate of success… sort of similar to my early success rates with mystery dates; but applying the formula here will simplify the analysis and should raise the success rate greatly. Thanks for “mathecizing” the process.. Perhaps I should return the favor by writing an article on “Finding the Perfect Date by Applying the 5 Principles of Scorched Earth Dating”.

  • So… I saved this article to my account as advised, and had it right there when I needed it! This is the year for me to complete my bucket list #bangoutasweater – I happen to already have Field Guide No 12 and to already covet the Main Squeeze Cardigan… but I want a yarn that has more sheen than Rowan Big Wool. Today’s Snippets had the lovely post about worsted weight Hektos, and I started thinking about using 2 strands of it held together in place of the bulky Rowan.

    I’ve done the math and it seems to be almost perfect… will someone please confirm I’m doing this correctly before I buy all that beautiful yarn!

    Big Wool = 87 yards/100 g = 0.87 yds/g

    Hektos = 200 yds/115 g, so held double will be same length but double weight so = 200 yds/230 g = 0.8696 yds/g

    If my math is right, the grist of Big Wool and Hektos held double couldn’t be much closer!

    I would make the small Main Squeeze, which calls for 9 balls of Big Wool, which equals 783 yds. So I need 783 yds x 2 (1566 yds) of Hektos-held-double, which is 200 yds/ball so 8 balls.

    I’m excited that this math may be right, but if it’s not please tell me!

    Thanks so much for the inspiration 🙂

  • Okay but what if you have a pattern that calls for a specific yarn that’s no longer made? How do you find the Grist you need to aim for?

    • If you can’t find it for sale anywhere (eBay, Etsy), and can’t find the details listed anywhere (YarnSub, Ravelry), then you’ll have to do some detective work. You could ask in a vintage knitting forum, or try searching digitised newspaper and magazine archives to find an old advertisement that might have those details. You could also ask around some older knitters and see if they remember it.

  • Brilliant info! Thank you so much! I am an advanced beginner with a small stash of yarn I acquired over time without any projects in mind, and am I petrified to move forward for exactly these reasons. I am hoping to find the perfect pattern for a shawl to use gorgeous yarn that I recently got while in Quebec City, but have held off for fear that I would pick the wrong pattern and run out. Will put this to work ASAP!

  • Another excellent resource. Thanks so much for drawing back the curtain for me!! Reading this helped me to avoid yet another substitution problem. The original yarn was discontinued, and I thought I had chosen a good substitute. Once I ran it through the calculations that you detailed, I realized that the yarns weren’t really that similar at all. My second choice looks much better.

  • Mucho thanks!

  • Thank you very much. I have magazines with sweaters that i want to make but can’t fnd the yarn. This will help with subtitutions.

  • How do you save this article when it does NOT have a bookmark symbol. Great article I will now hit my stash of unlabeled orphans. Thank you.

  • I had a vague idea about “density” or “firmness” when substituting, but this is the first time I find out there is a specific term for it. Thank you!

    Gotta say, the math examples made me grateful I live in a country that uses metric.

  • Does anyone know if there’s a collection or spreadsheet of YPP/ grist calculations that have already been done on popular commercial yarns?

    • Can calculate by exporting ravelry stash and dividing initial yards by initial grams

  • MDK articles are such a fabulous resource, thank you. And the writing always keeps me coming back for more. This: “yarn sub dud date territory” is genius! 🙂

  • I hadn’t known the term, but have been doing this for quite some time. I often knit from my stash, with yarns no longer in production and written about (ahem). Conversely, in my “library” of knitting books the yarns featured are most often not what is available, either.

    Great information (plus, confirms my method which I’ve tried to explain before to incredulous LYS people and other longtime knitters)!

    Thank you!

  • Fantastic information, thank you! Have been knitting for decades and had never heard this term, ‘grist’.
    I did not think of the word ‘gristle’, but rather a grist mill, which carries a less unsavory mental picture. 🙂 Thank you again!

  • Thanks for this post. I read it once or twice before, but I wasn’t “ready” to understand it yet. Now I have more spinning experience and better yarn understanding in general and finally was capable of getting this!

  • THANK YOU! for such a great explanation of grist. I find I rarely use the yarn the pattern suggests, much of the time because I need to use a plant based fiber rather than an animal one (I have cranky skin-booo). Do you have further info beyond that in your article on grist with information on how to successfully make that kind of substitution. I know there may not be an exact or perfect alternate but any info you have to share would be helpful

  • Jillian,
    Thank you! I too have been knitting for 30 years and substituting yarns has always been a tricky problem.
    Thank you for teaching me about grist
    I have a stash that I am going to go look at and give your process a try.

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