Will it be okay to use "all at once" instead of "in one sitting"? I mean in AmE what would sound more natural? Do they have a slight difference in their meaning?

  1. I read the book in one sitting/all at once..

  2. I watched an entire season in one sitting/all at once. (I know that "binge watching" is better, but I wanted to know about "all at once")

  3. I ate the whole cake in one sitting/all at once.

  4. I drank the whole bottle of water in one sitting/all at once.

  5. I typed the whole script out in one sitting/all at once

  • 1
    Can I ask why you're specifically asking about AmE? I would imagine you are trying to ask if this is natural in AmE rather than the grammatical accuracy, since that would be the same for both AmE and BrE
    – Gamora
    Commented Jul 16, 2019 at 12:21
  • Because it will be more natural to use "in one go" in BrE I guess @Bee. Commented Jul 16, 2019 at 13:50

2 Answers 2


The two phrases have similar meanings but are not synonymous.

In one sitting - During one uninterrupted period of time. Source: The Free Dictionary (Idioms)

All at once (in the literal sense) - Simultaneously (Happening, existing, or done at the same time.) Source: The Free Dictionary (Idioms)

"All at once" can also be used figuratively to mean suddenly (same source)

In my opinion (although I'm BrE, hence my hesitation to answer), non of the phrases you have provided sound natural with "all at once". However, there is a case that can be made for them using the phrase in a figurative sense.

I.e. You didn't literally drink the bottle of water in one go, but you drank it so quickly, that the situation was afterwards described as such.

Here are some suitable sentences which could use all at once in a literal manner:

We can't all get up at once. - Multiple people

The memories came flooding back to me all at once. - Multiple memories

  • Well, an American told me that Commented Jul 16, 2019 at 16:44
  • An american told you what?
    – Gamora
    Commented Jul 16, 2019 at 16:44
  • Maybe it isn't an idiom or a set phrase, but maybe it's about the use of "once". Like:"I ate the cake all at once and didn't divide it over a few days." Commented Jul 16, 2019 at 16:45
  • He told me that "all at once" can be used in a few sentences instead of "in one sitting". (In a few, but didn't tell me which ones) Commented Jul 16, 2019 at 16:46
  • That's not a good way to use that phrase. Whether BrE or AmE I haven't found any evidence of the definitions changing. The above sentence has to be figurative (since you can't literally eat the cake all at once) but it still makes more sense to say in one sitting because of the way you've clarified that the alternative is "over a few days". I wouldn't mix figurative and literal in the same sentence. You can also eat it "all in one go". There is a post about that on EL&U SE already.
    – Gamora
    Commented Jul 16, 2019 at 16:49

I think "all at once" may not be suitable for many of these sentences. Macmillan dictionary describes it as "very suddenly".

Following userr268429's comment, I stand corrected, "in one sitting" is idiomatic for doing things without stopping.

Another adequate phrase for these examples is at one fell swoop, which was likely coined by Shakespeare.

  • 1
    In one sitting is an established idiom. (–1)
    – user3395
    Commented Jul 16, 2019 at 13:48

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