be down to (one)

To be someone's duty, decision, or responsibility. After your father retires, it will be down to you to lead the company. So I guess it's down to me then. You still can't get ahold of anyone in IT? Well, I guess it's down to me to fix the printer then.

be down to something

COMMON If something is down to something else, the second thing is the cause of the first. When you are asked to score goals, then a lot is down to confidence and Kevin has that. I think that the show's popularity is down to two things.

be down to somebody/something

(informal)
1 be caused by a particular person or thing: She claimed her problems were down to the media. ♢ Our defeat in last week’s game is down to the goalkeeper, who played very badly.
2 be the responsibility of somebody: It’s down to you to check the doors and windows before we leave.

be down to something

have nothing except one or a few items of the kind mentioned: I’m down to my last penny.