off the top of your head

off the top of (one's) head

From memory; without much or careful consideration. A: "How much can we expect to earn this quarter?" B: "Off the top of my head, it should be around $200,000, but I'll have to check the figures when I get to the office." I know of two people who are coming off the top of my head, but I'm pretty sure more have also booked in. John can list the capital cities of all fifty states off the top of his head.
See also: head, of, off, top

off the top of your head

If you say something off the top of your head, you say it without thinking about it much or without trying to check it or find out more facts about it. I can't remember off the top of my head the date of the wedding. I'm thinking off the top of my head here. OK, off the top of your head, do you know the capital of South Korea?
See also: head, of, off, top

off the top of your head

without careful thought or investigation. informal
1988 Jamaica Kincaid A Small Place He apologises for the incredible mistake he has made in quoting you a price off the top of his head which is so vastly different (favouring him) from the one listed.
See also: head, of, off, top

off the ˌtop of your ˈhead

(informal) as a guess; without having time to think carefully: Off the top of my head I’d say it would cost $2 000 to do the repairs.‘What’s the population of Liverpool?’ ‘I’m afraid I couldn’t tell you off the top of my head.’
See also: head, of, off, top