The answer to the question of how much yarn is needed for a project is exactly the same as the answer to "how much fiber do I need for my project". It depends. The size of the project, the technique for making up the project, use of patterning in the project - all of these things together determine how much yarn is needed.

Those who knit or crochet but do not spin have it easy. Published patterns tell them how many skeins of a specific yarn to buy. Occasionally these patterns will also list yardage which is very important information for spinners because that's the figure we need - yardage. So, with a project in mind, how do we figure out how many yards of yarn we need to spin to have enough to make the project up?

The fleece is washed and waiting. The first step is to spin up a generous sample of the yarn we want for the project. A larger sample will give more accurate information. Spin and ply the yarn, wet finish it in the same manner as you plan to wash your completed project, and hang the yarn to dry. Then weigh the dried yarn and measure the length of your sample skein(s). Here is the formula for computing the number of yards per ounce of prepared fibers:

Length = Yards per Ounce
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Weight

Say the finished skein weighs 4 ounces and is 240 yards long. That gives us a yield of 60 yards of yarn for each ounce of prepared fibers.

If the pattern for the project gives the yardage needed, then all we need to know from here is how many 4 ounce, 240 yard skeins will be needed. Let's say the pattern calls for 1500 yards. 1500 divided by 240 = 6.25. We need 6 1/4 skeins.

To figure how much prepared fiber is needed to spin enough yarn, simply take the number of skeins needed and multiply by the weight of a skein. 6.25 x 4 = 25 ounces or 1 pound, 9 ounces of prepared fibers.

But what if the pattern doesn't state the yardage and the information is not available on line or from a local yarn supplier? Or what if our yarn is different from the yarn the pattern calls for? Well, then we need to do just a tiny bit more math.

Let's say the project is a sweater. The first thing we need to do is figure the area of the sweater. This takes just a few simple measurements. Get out a sweater that fits you well and measure it from the top of the neckband down to the bottom of the ribbing...call it 25 inches. Measure around the body of the garment at the widest point...say 40" inches. Multiply 25" x 40" = 1000 inches. Then measure the width of a sleeve at the widest part and from seam to seam... call it 18". Next, measure the length of the sleeve from the uppermost point of the sleeve according to your pattern down to the bottom of the cuff...say 17". Multiply those two numbers. 18" x 17" = 306" and multiply this by 2 = 612". Add the 612 to the 1000 = 1612". That is the total area of the sweater.

The next step is to figure out how much yarn is needed to knit 1612". To figure this out, a swatch will be needed. Make the swatch in the same technique and pattern as is planned for the sweater. A larger swatch is preferable as it will give more accurate measurements. Wash and dry the swatch, then measure its length and width.

Length X width = the area of the swatch. Let's say the swatch is 12" x 12" which gives it an area of 144 inches.

Then find the length of the yarn in the swatch.

Weight of the swatch (ounces) X Yards per Ounce = Yardage of the swatch.
Say the swatch weighs 3 ounces and our yarn measures at 60 yards per ounce = there are 180 yards in the swatch.

We now have enough information to calculate the total yardage needed for the sweater. Take the total area of the sweater and divide by the area of the swatch. 1612 divided by 144 = 11.2 which is the number of swatch sized pieces needed. Multiply the yardage in the swatch 180 times the number of swatches 11.2 and that's 2016 yards needed.


Lastly, we have to work back to how much prepared fiber and from there to how much grease wool we need. Here are the formulas for that:

Wt. of wool in yarn X 100 = weight of processed fibers needed.
__________________
% of washed wool*


Wt of washed wool X 100 = Weight of grease fleece needed
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% of grease wool*

* The formulas for figuring these percentages are given in my article "How Much Fiber Do I Need".