Mac storage basics · Finding big files, Downloads and the Trash
What's the quickest way to clean up my Downloads folder?
Short answer: Sort Downloads by Size, then by Date Added; delete used installers, disk images and archives, and move anything worth keeping to an external drive or the cloud.
Open Downloads in Finder, switch to List view and sort by Size to deal with the biggest items first, then by Date Added to spot anything old. Installers, disk images and archives are usually the easy wins.
For anything you might want later, move it to an external drive or cloud folder rather than keeping it on your Mac. Storage Studio's What's Using Space includes Downloads in the places it checks, and you can move the whole folder's contents to an external drive with a link left behind. See moving folders.