How to Knit a Helpful Swatch – Part 4 Swatching to Estimate Yardage Needed

I have covered the basics of how to make a Gauge Swatch and calculate your stitch and row gauge in my previous three posts. Today’s topic will cover some basic math to help you estimate the yardage that you need using your yarn, your needles, and your gauge to make a sweater.

Let’s say you want to make a sweater using yarn from your stash and you need to know if you have enough to make it. To make this estimate, you need the measurements for the sweater you want to make. If you are using a pattern, the finished measurements should be stated within the pattern – ideally on a schematic. Some patterns may only state the desired measurements within the text of the pattern and you may have to read through to find them.  If you are making the sweater without using a pattern – you would use the measurements of the individual who will be wearing the sweater.

The image below shows a schematic for the back of a sweater of a drop sleeve sweater. The back is 28 inches long from the hem to the neck and it is 20 inches wide. Both the front and the back of this type of sweater are essentially rectangles. 

Schematic of Back/Front of Sweater

The schematic for the sleeves of this sweater are shown below.

Schematic of Sleeve

At this point, you have the numbers you need to calculate the number of square inches of fabric that you need to make for this sweater. For the front and back, multiply the length by the width on the schematic and then multiply that number by 2. Using the numbers from my example above:

20 * 28 = 560     560*2 = 1120  square inches for front and back.

The sleeve is a trapezoid shape. The formula for the area of a trapezoid is:

[(b1+b2) * h] / 2

Where b1 is the width at the bottom of the sleeve(8”) and b2 is the width at the top of the sleeve(15”) and h is the length of the sleeve(18”). Using the numbers from the sleeve schematic, the area for one sleeve is 207 square inches. Since you need two sleeves, you then need to multiply the area of the sleeve by two. (414 square inches)

Now, here’s a short cut – if you place your sleeves next to each other so that the tops of the sleeves are parallel – you have a parallelogram. To get the area of this parallelogram you simply multiple the width(15”+ 8” = 23”) by the length(18”). Try it – you’ll get the same number as above.

Add the square inches for the front and back to the square inches for the sleeves and you have the total number of square inches of fabric in the sweater. Now that you know the total number of square inches of fabric you need, you will need to use the yardage and weight information of the yarn you want to use to estimate how many skeins or balls of yarn your sweater requires. The yardage per weight of the yarn will be found on the yarn label – see image below:

You will use the yards per gram value in the estimate for total yardage. Now you need to knit a swatch. The swatch should be in the same stitch pattern that you plan to use for the body of your sweater. This swatch does not need to be the same size as your gauge swatch, but it should be wide enough and long enough to get an accurate weight, length and width measurement.  After you knit this swatch, you will measure its weight using a scale that measures to the nearest tenth (0.1) of a gram. Next measure the length and width of the swatch and multiply these values together. This gives you the number of square inches in your swatch. Now divide the number of grams by the number of square inches.(Do not round). You now know what 1 square inch of your yarn weighs. This is the number you need to calculate how much yardage you need for your sweater.

Example: My swatch measures 3.5 inches by 4.5 inches, which gives me 15.75 square inches. The swatch weighs 9.6 g. Dividing 9.6 by 15.76 gives me 0.622 g/square inch.

Here’s the final set of calculations:

Take the total number of square inches of fabric and multiply it by the number of grams per square inch. This gives you the total weight in grams for your sweater.

Total Number of Square Inches * grams/inch2  = Total grams of fabric

Total Grams/Square Inches = (1120 + 414) * 0.622 = 954.148 g

Now take the yards per gram value from the yarn label. (For example 218 yds/100grams). Divide the yds by the grams to get the number of yards in 1 gram of yarn.  (For example: 218yards/100grams = 2.18 yards per gram.)  Multiply the total number of grams of fabric by the number of yards per gram to get the total yardage for the sweater. Using the numbers from the examples above:

Yards per gram = 2.18 yds/g

Total Yards of Yarn = 954.148 * 2.18 = 2080 yds

To determine the number of skeins, balls or hanks of yarn you need: Divide the number of yards by the number of yards in the skein. Or divide the total number of grams by the number of grams of the skein.  Remember that you will want one extra skein for swatching. (In my example, I would need 9.5 skeins, so I would want 11 skeins with one extra for swatching)

What to do if you don’t have the yarn label

To determine how many yards of yarn you have when you do not have the yarn label or any information, simply measure out 10 yards of your yarn and weigh it. Divide the weight by 10 and you have the weight for 1 yard of yarn. Now weigh the skeins/hanks of yarn and multiply by the weight of 1 yard.  This will give you the number of yards for each skein/hank.


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New Local Yarn ShopsNew Local Yarn Shops

I recently visited two new yarn shops that opened in my area.  They are both lovely shops and filled with some lovely yarns – some of which aren’t carried by the local yarn shop that has been the only shop in the city for a number of years. Each shop offers a different variety of yarns than the other, so I am hoping that both of them can be successful.  We certainly have a growing number of knitters in our community, so having new yarn shops is quite appealing.

ImagiKnit Yarn Shop is located in the Bel-Air Plaza at 120th and West Center Road, Suite 602, Omaha, NE. This shop does not have a website, but does have a Facebook page: https://www.facebook.com/pages/ImagiKnit-Yarn-Shop/263171999129. The owner of this shop moved her business to Omaha from Hastings, NE.

Wooly Mammoth Yarn Shop is located in Rockbrook Shopping Center at 108th and West Center Rd, Omaha, NE. This shop also does not have a website, but does have a Facebook page: https://www.facebook.com/pages/Wooly-Mammoth-Yarn-Shop/150211221662670. The owners of this shop recently moved from Kearney, NE.

I’m sure the knitters in Hastings and Kearney miss having the shops in their towns, because they are both wonderful yarn shops and we are very lucky to have them here in Omaha.

Appealing, as well, are the yarns I purchased from both shops. (I couldn’t resist).

From Imagiknit, I purchased a skein of Smooshy fingering weight yarn from Dream in Color. The colorway is 2014 September and it just spoke to me of autumn.  It has this delightful mix of fall colors: reds, purples, golds, greens in various shades. See the swatch below

.Swatch with yarns

I also bought a skein of Fabjous Fibers Cheshire Cat in the colorway Off with Her Red – which blends perfectly with the Smooshy colors. I am using these yarns to knit a shawl using the Merlot pattern, which I purchased at Ravelry. This will be the topic of another post.

From Wooly Mammouth, I purchased 4 skeins of Addiction yarn by Claudia Hand Painted Yarns – also fingering weight yarn. I bought 2 skeins in the colorway Teal and 2 skeins in the colorway Prussian Soldiers. I plan to knit another two color shawl using these yarns, but I haven’t decided on a pattern yet. I like the Merlot pattern, so I may choose to do that again – but there are so, so many lovely shawl patterns in my queue…

If you are in Omaha: check out our new local yarn shops.  🙂

The Roomba Ate My Socks!The Roomba Ate My Socks!

Roomba
I have a Roomba – which is a small robotic vacuum cleaner. You are supposed to be able to contain it to a single room using little devices called “lighthouses”. I really like this little guy for frequent vacuuming of my kitchen. So, the other day, I turned it on and left it to run around the kitchen while I did some things in my office.

Well, it escaped the kitchen and headed off into the living room – where my two at a time socks using magic loop project was laying beside my recliner (I’d left them there the night before) …AND…the Roomba ate my socks!

I heard this weird little sound coming from the living room and went to investigate – and there I found the Roomba thrashing about entangled in my 40” circular needle and the yarn from one of the socks. (I was so traumatized that I forgot to take a picture.)

After turning the Roomba off, it took me several minutes to remove the yarn from around the various moving parts and then deal with the fact that the circular needle had somehow ended up wrapped around one of the wheels. Eventually, I succeeded in extricating my circular needle – but it was a close call, as I had begun to consider the possibility of having to cut the cable. (WHEW!) Fortunately – one sock was still on the circular needle. The other, however, was laying in the middle of the floor – off the needle and minus its ball of yarn. I tenderly picked up this wounded creature and set it aside to recover from all the trauma.

I discovered that the lighthouse that should have prevented Roomba from going into the living room wasn’t working (dead batteries). Once I replaced the batteries, the darn little thing worked just fine and stayed in the kitchen where I wanted it to be.

Socks_BackTog
Happy News! – I was able to frog the wounded sock back to a point that I knew where I was in the pattern and then pick up the stitches and reconnect the yarn to the sock as I reknit it back to where it had been before it was attacked by the Roomba. It is now back on the same circular needle with its brother.

Knitting Socks in Waiting AreaKnitting Socks in Waiting Area

Yesterday, I had the role of being supportive of my DH while he underwent some tests at our local hospital. (Nothing serious, just part of routine maintenance for the over 55 crowd.)

Anyway, I decided to take along a pair of socks I am knitting as my “keep occupied” project for the time I would be sitting in the waiting area. I am doing cuff down, two at a time on 2 circular knitting needles. So I pulled out my knitting and started to knit away while I sipped on a cup of coffee. An older woman walked into the group of chairs where I was sitting — and pulled out her knitting!

She was knitting something on dpn’s in a pretty dark green yarn. For a time, we sat and knit without any conversation. Then, she put away her knitting and came over and sat next to me and chatted. (I think she was anxious about whomever she was waiting for, but she never really said.) I learned that she was working on a pair of mittens and she was very curious about the method I was using for knitting socks and my self-striping yarn. We exchanged bits of information about yarns and knitting and then she was called to go back with her family member while he/she recovered.

It’s interesting how knitting forms a link and an introduction for us. I know it made the time in the waiting room go by more quickly for me and I’d like to think it eased my companion’s anxiety a little and helped her time in the waiting room pass more pleasantly.

P.S. Started the socks so that I would have an easy knit project for the knitting guild meet ups. More on the guild in another post. I promise to post a picture of the socks when done.