How long is a cut onion still good in the fridge?

Really depends on the fridge. How long do your veggies usually last?

I’d say 5 days.

As long as it hasn’t turned mushy, slimy, or brown it’s fine. I’ve had some last for a week or two. Depends on what state it was in when you bought it.

Vidalia onions and red onions tend to spoil more quickly than others.

Andrew has it right. Exactly five days.

If it’s still crisp and smells like an onion, it’s fine. If it has turned into something you don’t recognize, or smells like something else, give it the heave-ho.

I don’t know, seems like onions last forever to me. I’ve had my current onion for almost 2 weeks and it’s perfectly fine. It’s just now starting to dry out, but it’s not rotten at all.

It varies depending on the sugar content of the onion, your fridge temp, the packaging. Go by looks. I agree with @Buttonstc and would add or is all dried out. If old, it may become “hot.”

I agree with ubersiren, I’ve had some since 1976! Not really, but they do seem to last at least a few weeks in my fridge, generally longer than many other veggies. I usually am using your basic yellow onion.