off the top of your head
This page is about the idiom off the top of your headINFORMAL
If you give someone information off the top of your head, you do so from memory, without checking beforehand.
- I can't tell you Maxine's phone number off the top of my head. I'll have to check.
- I don't know for sure, but off the top of my head I'd say that renting a two-bedroom apartment would cost about a thousand dollars a week.
The one thing that everyone can tell you off the top of their head is
Contributor: Matt Errey