I’ve got a BIG project I just agreed to. I can’t tell you a lot about it yet. But I spent most of my weekend crocheting up swatches to figure out the amounts of yarn I would need to finish the samples for the project.
The pile above is what I ended up with. Some of these yarns are just too lovely for words and I am really looking forward to crocheting the final pieces.
Next step, as I wait for yarn to arrive, is to write the first draft of the patterns for these designs. Because I am a geek I tend to swatch, do a bunch of math, write the pattern, then work the sample from that pattern. It is the method I’ve found works the best for me. Then I can make corrections or additions to the pattern as I encounter trouble spots while stitching.
An example of this process was my Winged Columns Wrap in the Crochet! Magazine presents: Fall 2014 Special: Crochet Gifts in 1-2-3.
Originally I submitted the idea for a smaller accessory, but had included a sketch and description of it as a rectangular wrap. The editor decided she wanted it as a wrap. She and I discussed the size of wrap she wanted. We decided on approximately 18″x 60″.
I then swatched with the yarn she had chosen, Premier’s Alpaca Dance. My swatch was 6″ x 6″. I then weighed my swatch in grams. That allows me to calculate how many yards of yarn are in the swatch. According to the ball band information there are 371 yards in a 100g ball of yarn. So 3.71 yards/gram.
The target size of my finished stole was 18 x 60 = 1080 square inches. My swatch was 36 square inches and took 23.4 yards to make. 1080 divided by 36 = 30. 30 x 23.4 = 702 yards. Which means I needed 2 balls of yarn to make the sample.
Now, how does this all help you?
Have you ever wondered if you have enough yarn to complete a project? Swatching in the stitch and yarn you will be using, then weighing it can get you there. Once you know the weight of your swatch and what size your final project is supposed to be, you can tell if you will need to go purchase more yarn.
Of course, once you are purchasing yarn you might find some other yarn that needs to join your household too. Yarn shopping does tend to add to our stash. But using the above formula, you’ll always know if you’ll need more yarn for the current project (or the next one).
Mamas2Hands 
I make all my swatches 10″x10″ and then sew them together and make afghans. I’ve done this for years and have given the afghans as gifts. I’ve even given some to a local charity for the homeless. It’s a productive thing to do with something that you have to do anyway.
That is a great idea when you are working with similar yarn weights and fibers for all your projects. You can even do it with swatches that are different sizes and shapes. Create a “Crazy Quilt” kind of afghan.
When I design I often try to have the “swatch” be part of the finished project, so stitchers don’t feel like they have to waste their swatch. When making garments it’s also a good idea to hang onto the swatch to have the extra yarn available in case you have to do repairs on the garment.