3 stitches = 2.5 cm in double crochet (US) with larger hook

This pattern is available as a free Ravelry download

Round height gauge isn’t important because you can just add on rounds

More yardage will be needed to make a longer hat.

Hook sizes were recently changed/updated - Please get Gauge!

fantasiedinephtys has translated this pattern to italian.

She has also created a cowl to match the hat! Pattern is here, but it’s in Italian only.