what am i doing wrong when i mass delete emails on gmail?

search first, then select all. older_than:1y or from:someone in the search box and you only wipe that batch rather than everything. category:promotions is the big one for clearing space fast.

The tick box at the top only grabs the ones currently on screen, which is why it feels like nothing happens. After you tick it, a small line appears above the list offering to select all conversations that match the search — click that first, then the bin. That's the step people miss. Do it on the desktop site as well. The phone app has no select-all, so you'd be tapping for the rest of your life. And deleted mail sits in Bin for thirty days still counting against your storage, so empty that too if space was the reason.