Over the years, I have often debated whether the phrase is "In the morning, I'm going to sleep in." or "In the morning, I'm going to sleep out." My best guess is that it is a regional difference of convention.

Is it? Are there any real, historical or otherwise, reasons to prefer one over the other?

(It would be particularly nice, arm-chair linguistically, if it were "I will sleep out." but "I slept in.", though I quite doubt that fits anyone's usage.)

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    FWIW: I have lved everywhere and I have never, ever, ever heard "sleep out" to mean "sleeping late." "Sleep out" means sleeping outside.
    – Fattie
    Jul 4, 2011 at 11:30
  • Among the Irish authors I've read, I've only ever noticed it in Roddy Doyle: There's another reason he's late. He slept it out. --Well, he says. Declan never sleeps it out. Never. But the days just caught up with him; he hadn't slept since he'd arrived in New York. (Home to Harlem, from The Deportees and other stories)
    – MT_Head
    Jul 4, 2011 at 17:05
  • @cindi - Good catch! In my defense, I did say "noticed", not "read"... I'd completely forgotten about Beckett! I was just thinking about WfG yesterday, but I haven't read it in years (and I've never seen it produced.)
    – MT_Head
    Jul 4, 2011 at 18:01
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    I've seen the phrase "to sleep oneself out" in American English to mean "to sleep until one doesn't need to sleep anymore," but that doesn't sound like what the OP means...
    – chama
    Jul 4, 2011 at 18:44
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    @cindi @head hmm, "slept it out" is a different phrase. I've never heard "slept out" used to mean "slept in". But if you say it's Irish, OK!
    – Fattie
    Jul 5, 2011 at 5:04

2 Answers 2


The normal American English would be sleep-in if you plan on doing it on purpose or over-sleep if you do it on accident. Confusingly, sleep-over is different and refers to sleeping at somebody elses house. In the usage you describe, sleep-out is just a variant of sleep-in. The references I found were either British or ESL usage that looks like a second-language mistake. It doesn't look like it's a very common variant, you should stick to sleep-in. Here's the ngram

Ngram for sleep-in vs. sleep-out


I would say, no, it wasn't regional usage, and they aren't preferred over one or the other. They're just used in different places. "sleep in" has a different meaning from "sleep out".


a person who lives elsewhere than at the place of employment.
an act or instance of sleeping outdoors.

"Sleep-in" :

(intransitive) (idiomatic) To sleep late; to go on sleeping past one's customary or planned hour.

So, if you were going to "sleep late in the morning", I would use "sleep in", but if you were going to 'have a nap in the garden', I would use "sleep out".

That's my two coins.

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    No. Just no. Read the context that the OP posted. If they were planning on sleeping out of doors, they wouldn't be doing it just in the morning! Vary rarely does one go to bed normally and wake up outside in the morning.
    – Caleb
    Jul 4, 2011 at 16:03

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