About six years ago, I posted about how to calculate the percentage of a circle that’s been knit, based on how many rounds have been worked. I’ve updated the post a little bit while I was at it.
Shorter version: starting from the center of a circle, a quarter of the yarn will have been knit at half the rounds. Half the yarn will have been knit at about 70% of the rounds.
This also works for other shapes that start with a small number of stitches and increase at a steady rate.
I don’t know that this works for pi shawls.
(How have I been blogging for six years?)