How to calculate the yardage of your crochet or knit project:

by Isabella


Posted on May 28, 2021


Have you ever needed to know how many yards of yarn you used in your crochet or knit project? Or how many yards of yarn you have left over? I am no mathematician, but this number can SO crucial to know for so many reasons. As a designer, I calculate this out all of the time to provide suggested yardages for patterns, but it’s also vital information if you’re pattern testing for someone (me?!), as the designer needs to know how much yarn it took you to complete the project.

But even outside of designing or testing, being able to calculate yardage is super handy! Do you sell finished items? Being able to tell exactly how much a a skein you use to make a product is helpful when purchasing yarn for the season – how many skeins do you need for your desired amount of inventory? Being able to math out yardages is also helpful when you have left over scrap skeins and you are wondering if you have enough to complete a certain project. I am going to show you the SIMPLE math that will allow you to calculate exactly how much yarn you used in any crochet or knit project!

I remember the first time I tested a pattern, I had NO idea how to provide this information. As it turns out, telling a designer you used about 3.5 skeins is NOT helpful. Like do you get a yard stick and measure a whole lot of tangled yarn? Do I stand on my scale without the sweater, then put the sweater on and then do some magic math to tell the difference? Thankfully, no. With this math equation you will be able to tell almost exactly how much yarn you used (or how much yarn you have left over) to complete any given crochet or knit project.

Remember cross multiplication from like 5th grade? Or Algebra? Let me refresh your memory! Again, I am NOT a mathy person, but I promise this is basic, and all you need is some yarn and a postal or kitchen scale. And let’s be a real, a calculator, cause I ain’t doing math without a calculator. That’s just madness.

As far as scales go, anything that measures accurately in ounces and grams will do ya just fine, and you kind find all sorts of kitchen/postal/jewelry/coffee scales that will do just that. Personal preference, I like a kitchen scale. I used to work off a postal scale, but I found, at least the model I had, was great for heavier items, (like a package being shipped) but not great with little scrappy bits of yarn. Jewelry and coffee scales kinda go the opposite way, in that they are great for itty bitty increments, but not great if you need to weigh a whole sweater. And bathroom scales tend to only weight in pounds/kilos, so that won’t be ideal for working with yarn. Kitchen scales are the perfect happy medium for yarn related items.

Ideally, you NEED something that measures in both ounces and grams, has a tare feature, and measures in incriments of .1 oz (1g). My favorite is this one- The Escali Primo. You can get it off Amazon (affiliate link), it’s very budget friendly (under $25!), and it comes in bunches of cute colors. And I’ve found it very reliable and accurate! It is definitely a favorite within the fiber arts community, but if you have something similar already, you’re good to go!

Now there are kind of two ways to go about this. You can either weigh your finished object- like putting your whole sweater on the scale- to tell you how much you used. Or you can figure out how much you have left, by knowing how much you started with, and then calculate how much you used based off what you have left over. Either method, all the information you will need about the yarn should be found on the back of your yarn label.

Yarns are typically measured in yards per grams in the USA, but you can use this same method to calculate meters per grams as well, depending on where you are! Sometimes skeins are measured in ounces too. Again, you can convert the math as necessary, I’ll just be sticking to the basics here. Just make sure whatever numbers you plug in, you’re consistent (ex: if your finished skein in 100 grams, make sure you measure your object in grams and not ounces, or you’ll have to do some conversions too!)

For purposes of this example, I am using a fingering weight, indie dyed yarn by Life in the Long Grass that is 460 yards per 100 gram skeins. But this works with ANY YARN, in any form of measurement, as long as you either have the ball band, or can look up that information.

Little disclaimer here: if you want to be REALLY precise, like for designing, or giving a designer feedback, weigh your skeins, without bands/labels on, before you start making anything. Just cause it says 100 grams on the label, doesn’t necessarily mean it’s exactly that. Often there can be variation between like 90 grams and 110 grams. Double check if you want really solid maths, and use the actual weight of the skein and not just what the band says!

For accuracy, it is best to weight your objects or yarn inside of a bowl or container that fits completely on the surface of your scale. So find a container, place it on the scale and hit the “TARE” button. This will zero out how much that container actually weighs, and more accurately calculate how much your yarn/objects weighs, without it flopping over the edges and not fitting on the scale’s weighing surface properly.

Here’s how it works:

So knowing that in my one skeins I have 460 yards per 100 grams, I can math this beast out. Just for example sake I am going be weighing a couple swatches I made in this yarn to tell me how much yarn I have left over to work with. However, you can do the same thing with an entire finished object, or you can reverse it and weight the left over yarn, and do a lil subtraction from your total skein to tell you how much you used. Sometimes I do both methods just to check for accuracy!

Okay, let’s take it step by step:


Step ONE: Fill in the red and yellow boxes with the information you already have (for me, I know my full skein was 460 yards, and weighed 100 grams, and that my pile of swatches weigh). Now we will solve for what we don’t know- how many yards of our yarn did we use?!

Step TWO: Multiply the numbers in the red boxes – your item weight and the yardage of a full skein – together. Jot that down on the side somewhere. (so 33 X 460 = 15,180)

Step THREE: Take the number you got from multiplying the red boxes together and divide that number by the yellow box – the weight of the full skein. (15,180/100 = 151.8)

Step FOUR: the number you got in step 3 is your answer! That’s how many yards (or meters, if you were measuring that way) you used in that item!

So, I used roughly 152 yards out of the total 460 yards in a skein to make those swatches. Easy, right?

And it’s very easy to tweak this method to work for exactly what you need to measure. More often than not, I go the method of weighing how much yarn is left to find out how much I have used of my skein(s), especially if it is piece that used multiple colors (where weighing the total object wouldn’t make sense if you needed to know how much you used of each color! I also find it easier to just weight left over yarn bits, than to put an adult sized sweater in a bowl on a scale. But like I said, check both and make sure you’re getting the same/very similar numbers!

If I had been weighing left over yarn instead or the finished swatches, the equation would have been more like this:

67 grams of left over yarn x 460 yards total skein = 30,820

30,820/ 100 grams = 308.2, so roughly ~ 308 yards left in the cake of yarn. (and this checks out with my other math, knowing that 152y + 308y = 460 yards. BAM.)

And one more instance you might find helpful: calculating how many skeins I used. Say I made a sweater out of this yarn and the final thing weighed, lets say 475 grams when I finished. I would do 475g x 460y = 218,500 Then 218,500/100g = 2,185 yards. Then knowing that each skein was 460 yards, I can take 2,185y/460y= 4.75 skeins used. So if I was adding that to a pattern design, I would know you would need roughly 5 skeins to complete that particular size of the garment.

*designers: if you are calculating for recommended yardage in a pattern, I always round the answer up a bit, just to give a yarn chicken cushion. So like, if I found I used 1,411 yards for a sweater, I would likely list it in the pattern as about 1,420 yards for that size. Rounding up is always better than rounding down! But if you are calculating FOR a designer, just give them the number you got as your answer!

So there ya have it: yarn math! Hopefully you found this useful and will be able to apply it to all your designs, tests and projects. It’s such an important equation that can be applied to so many situations within the fiber arts community. And if you’re testing for me- I appreciate you and all your time and effort!

Any questions? Reach out! You can contact me at bella@fiberandfox.com if you have any questions on how to apply this to your project or test.

crochet math , pattern design , pattern tester , pattern testing , yarn scale , yarn yardage

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