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off the top of my head is the most popular phrase on the web.

off hand 14,980,000 results on the web	off the top of my head 121,100,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Got to work on your off hand. Turning to make yourself a smaller target, angling towards my off hand. My off hand's better than yours. Mister... have you seen a chopped off hand? Is there anything else that you can think of off hand? Setting off hand grenades and hiding in alleys? Not off hand, ma'am. My off hand's better than yours.	It just was off the top of my head. I couId give you half a dozen reasons just off the top of my head! Just off the top of my head I'd say your villain is Angela Petrelli. Off the top of my head, I'd say low self esteem, a lack of maternal affection and a genetic predisposition for anxiety and depression. I mean, off the top of my head I could think of half a dozen East European players who would have to be on that squad. I couldn't say off the top of my head. I don't know off the top of my head.

off hand

14,980,000 results on the web

off the top of my head

121,100,000 results on the web

More popular!

It just was off the top of my head.
I couId give you half a dozen reasons just off the top of my head!
Just off the top of my head I'd say your villain is Angela Petrelli.
Off the top of my head, I'd say low self
esteem, a lack of maternal affection and a genetic predisposition for anxiety and depression.
I mean, off the top of my head I could think of half a dozen East European players who would have to be on that squad.
I couldn't say off the top of my head.
I don't know off the top of my head.