Making sense of square to round ductwork transitions

Figuring out how to build a square to round transition can feel like a geometry headache you didn't ask for. Whether you're trying to hook up a new dust collector in your woodshop or you're knee-deep in a DIY HVAC project, that moment when you realize you have to connect a rectangular opening to a circular pipe is always a bit daunting. It's one of those things that looks simple until you actually have to hold the sheet metal in your hands and make it fit. ...

February 11, 2026 · 6 min · Ksenya Kierulf