It was the best I could think of off the top of my head.

这是我能马上想出的最好办法。

《柯林斯英汉双解大词典》

I can't remember the name off the top of my head, but I can look it up for you.

我一时想不起这个名字，不过我可以给你查一查。

《牛津词典》

He behaved like a seriously odd person, talking off the top of his head.

他表现得像个怪人，说话不加思索。

youdao

Are there other indicators or tricks or rules of thumb that just off the top of your head come to you as useful mechanisms for doings this as well?

当然还有没有其他的,一些暗示或者说技巧,或者规则之类有用的办法呢？

哈佛公开课 - 计算机科学课程节选

Alums with Nobel prizes? Oh, I don't... I can't think of any like, off the top of my head.

获得诺贝尔奖的校友吗？这个……我一时还想不出来。

知道约翰·纳什吗？ - SpeakingMax英语口语达人

I guess right now, off the top of my head, I'm really into, I've loved Kanye West forever.

我觉得现在，我脑子里想到的，我真的，喜欢肯耶·韦斯特，永远都喜欢。

只要是音乐就好 - SpeakingMax英语口语达人

Previously, he said he couldn't think of any right off the top of head.

CNN: Bush, Kerry bare knuckles in second debate

Reporters call me directly and I have to answer them off the top of my head.

FORBES: Creating And Conveying Your Media Message -Media Training

Those are just the things I can remember off the top of my head.

FORBES: Straying Off the Path or Changing Direction?