off the top of one's head

off the top of one's head

In an impromptu way, without much thought, as in Off the top of my head I'd say we'll double our profits in a year. This idiom suggests one has not used the inside of one's head before making some statement. [Mid-1900s]
See also: head, of, off, top
References in periodicals archive ?
Artistry can also come right off the top of one's head.