This is a recipe for custom length and circumference armwarmers made with any 100 gram ball of sock yarn you may have.

The pattern takes you through knitting a gauge swatch, the key measurements you need and how to do the math to design and knit elbow-length armwarmers that fit you (or anyone else).

There’s also a sample pattern to show how the math works that fits me. I have a 10-inch elbow measurement, a 6.5-inch wrist and my arm wrist to elbow is 9 inches long.

This pattern was on About.com (which no longer exists) and has been deleted from their site, but for now it can still be found on the Internet Archive. They redirect and delete pages a lot so you may want to download/print to save.