Whether you're following a pattern or designing your own, experienced people will have all the yarn they need for the entire project at once, because if your project spans too long, it's hard to make sure that the one you have isn't discontinued. What's more, there will be less difference in the color of yarns from the same dye lot. So, how much yarn do you need for your project? Too much or too little can be a headache. In this article, we'll do some simple math to teach you to estimate the exact amount of yarn you'll need.
Factors affecting yarn usage
Before we start our "math class", let's do a general understanding of the factors that affect yarn consumption, mainly the following four factors:
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Yarn weight: This is a very important factor. In crocheting, it is easy to see that thicker yarns tend to run out more easily, because thicker yarns take up more space in the work than thinner yarns. A visual representation of this is that a WPI, Bulky yarn can only be wrapped 7 times an inch, while a Fine yarn can be wrapped 18 times (depending on the strength of the individual there may be a slight difference).
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Stitch type: The more complex the stitch, the more yarn is needed, for example, a treble crochet in a basic stitch requires significantly more yarn than a single crochet. In addition, some textured stitches such as bubble stitches require more yarn than basic stitches.
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Crochet Hook Size: The diameter of the shaft of the crochet hook determines the size of the stitch. The larger the crochet hook, the larger the stitch will be, so your project will be looser and you may need less yarn. Conversely, the smaller the crochet hook, the tighter the stitch will be , and the more yarn you will need to complete the same size project.
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Crochet Tension: A tighter crochet will end up using more yarn for the same project.
How to Calculate How Much Yarn You Need for Your Project
There are generally two things that happen when crocheting a project: following a pattern or designing your own. Following a pattern usually tells you how many yards of yarn you need to use, so here we'll focus on how to estimate how much yarn to buy when designing your own pattern.
To crochet a gauge with crochet hooks, yarn, and stitches prepared for use in the actual project and measure it, here are the steps:
(1) Make a gauge swatch:
At least 4 x 4 inches, the larger the swatch, the more accurate the calculations will be, and the number of stitches can be kept to a number that is easy to calculate.
NOTE: Kindly first make sure the sample drapes to your satisfaction. If not, change crochet hooks to achieve the desired result. Secondly, don't leave the yarn too long in the last stitch as this will affect our final calculation.
(2) Measure the swatch:
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Calculate the total number of stitches in the swatch: we are counting in this swatch to determine how many rows there are in total and how many stitches are in each row. In the swatch size we crocheted, there are 8 rows (width) and 40 stitches per row (length). This gives us a total of 40 x 8 = 320 stitches.
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Calculate the weight of each stitch: Put the whole swatch on the kitchen scale to measure, the weight of the swatch specification is 33 grams (if your unit is ounces, the same), you can quickly calculate the weight of each stitch. Weight of each stitch = weight of sample gauge (g/oz)/total number of stitches in the sample,i.e. 33/320=0.103125 (if your weight is in ounces, the weight per stitch here will be very small, kindly record as many decimal places as you can to make it more accurate).
Then, let's say the project we need to crochet is a blanket that is 40 inches wide by 60 inches long:
(For ease of calculation, the following is counted in a 4×4 inch range for this swatch.)
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Rows per inch: there are 8 rows in the 4-inch range, so the number of rows per inch is: 8 rows / 4 inches = 2 rows / inch, the blanket is 40 inches wide, so we need 2 × 40 = 80 rows
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Number of stitches per inch: 4 inches within a total of 18 stitches, so the number of stitches per inch: 18 stitches / 4 inches = 4.5 stitches / inch. The blanket is a total of 60 inches long, so we need 4.5 × 60 = 270 stitches.
(3) Total project stitches: from the number of rows per inch and the number of stitches per inch, we can conclude that the total number of stitches for crocheting 40×60 inches blanket = 80×270=21600 stitches.
(4)Yarn Weight Needed = total project stitches × weight of each stitch = 21600 × 0.103125 = 2227.5 g
Checking the yarn label will tell us the yardage and weight of each skein of yarn, and we'll end up using the total weight/weight of each skein to find out how many skein of yarn to buy. In our example above, we need a total of 2227.5 grams of yarn, and if each skein of yarn to be purchased is 200 g, then we need to purchase 12 skeins of yarn (2227.5/200=11.1375).
This method also applies when calculating projects with more complex stitches, but be careful when making the swatch to make sure that the project's stitches have had several complete repeats in the swatch (the larger the swatch, the more repeats, the more accurate the calculations will be), and then to determine the weight of the swatch repeat stitches as well as the weight of each repeat, the yarn needed = the weight of each repeat x the total number of repeats needed.
*Tips: The calculated amount is only an estimate and you better add an additional 20% of yarn.
*Extension: How many yards of yarn do you have left over?1. Use a kitchen scale to weigh the remaining yarn for the project (in grams or ounces), assuming this number is A.
2. Assuming that the number of yards of yarn remaining to be counted is B, then this equation will hold A/B = weight of complete skeins / yardage of complete skeins.
Assuming the complete yarn weighs 140 g and is 500 yards, and we weigh the remaining yarn to be 25 g, then 25/B=140/500, we can figure out that B equals about 89 yards, so there are 89 yards of yarn left. Knowing the yardage maybe you can find a small project for that yarn.
Quick methods for estimating yarn weight
Here are two more easy ways to quickly get the amount of yarn you need：
1.Yarn Usage Estimation Form for Common Projects：If you find the calculations a real pain in the ass, you can quickly check out this table, but it's just a reference, and it's possible for it to deviate significantly depending on the specific situation（Table provided by Lionbrand）.
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Yarn Weight 1
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Yarn Weight 2
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Yarn Weight 3
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Yarn Weight 4
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Yarn Weight 5
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Yarn Weight 6
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Yarn Weight 7
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Hat
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250-325 Yards
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250-325 Yards
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200-250 Yards
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200-225 Yards
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125-200 Yards
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125-150 Yards
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30-60 Yards
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Scarf
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525-825 Yards
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450-625 Yards
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375-500 Yards
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375-500 Yards
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250-375 Yards
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250-375 Yards
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125-200 Yards
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Socks
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350-500 Yards
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300-450 Yards
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275-400 Yards
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275-375 Yards
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250-350 Yards
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200-250 Yards
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175-200 Yards
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Shawl
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550-850 Yards
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450-700 Yards
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400-625 Yards
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375-550 Yards
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350-500 Yards
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350-475 Yards
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300-400 Yards
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Adult Sweater
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3375 Yards
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1750-2625 Yards
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1500-2250 Yards
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1125-1625 Yards
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950-1125 Yards
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825-1125 Yards
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825-1125 Yards
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Baby Blanket
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1500-1625 Yards
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1250-1500 Yards
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1125-1250 Yards
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1000-1125 Yards
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875-1000 Yards
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750-875 Yards
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625-750 Yards
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Afghan
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3750-4125 Yards
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3500-3750 Yards
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3000-3500 Yards
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2250-3125 Yards
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2000-2250 Yards
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1625-2000 Yards
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1375-1625 Yards
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2.Web Calculators: such as the Crochet and Knitting Calculator, there are now many on the web that will give you a quick estimate of how much yarn you need by entering your project type, project size, and gauge swatch.
If this article helps you estimate the appropriate amount of yarn then it's all worth it! Also, if you have a little bit of yarn left over from a previous project that you don't know what to do with, head over to our free Small Projects Tutorial and hopefully it will help you make some cute little objects!
