Off the top of your head, can you name the capital of Madagascar? Antananarivo, of course!
This hugely popular expression is used in situations when you’re trying to recall something immediately, without thinking for a long time.
You’d probably use it to say something along these lines:
– Where do your boyfriend’s parents live?
– I cannot remember off the top of my head, it’s a small town in rural Austria. We haven’t visited them yet.
Let’s turn to the media for some more examples of usage:
– In addition to the critics’ choices, we would like to know your favourite British building. You can answer this off the top of your head, or take time and think your answer through (The Guardian).
– This type of planning takes time: you can’t dash a plan off the top of your head (The Guardian).