This is actually more like a recipe than a pattern. My donut turns out to be just shy of an inch in diameter. You can make it smaller or larger by using a lighter (fingering, embroider thread?) or heavier (worsted) yarn, and changing hook size accordingly (2mm for finer yarn and 3.5mm for worsted, for example). You can also make a larger donut by increasing the number of beginning ch by multiples of 2, and repeating round 3 a couple of times. I wouldn’t start with fewer stitches than what the “recipe” calls for though, it can be really tricky to manage such small number of stitches.

The entire donut only consists of 5 rounds! You can make an army of them in an evening :D