• 3-minute read
  • 4th June 2018

Word Choice: Quick vs. Fast

Whooosh! Zooom! Wheee! Today, we have a need for speed, so we’re looking at the words “quick” and “fast.” Both terms are related to rapidity, but there is a subtle difference between them that many people overlook. So, join us for a speedy look at how to use these words correctly!

Quick (Speedily or in a Short Time)

One use of the adjective “quick” is to refer to something that happens at speed:

John was always quick to respond.

The emphasis here is brevity of action. We also see this in another use of this term, which is to show that something happens in a short amount of time:

I’ll give your essay a quick look before you hand it in.

These uses are similar, but the second doesn’t necessarily require speed. You could have a “quick nap,” for example, which would be short but static (unless you fall asleep on a skateboard at the top of a hill).

Seems like a good spot for a “quick” nap.
(Photo: John Chapman/Pyrope)

The adverbial form of this word is “quickly.” “Quick” and “quickly” are sometimes used interchangeably, but you should always use “quick” for nouns and “quickly” for verbs in formal writing.

Fast (At High Speed)

“Fast” is another adjective that refers to something happening at speed:

John was always fast to respond.

However, it can also be used to describe something that is capable of moving quickly. Or it can indicate that something happens at a high pace:

I’ve always loved fast cars.

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The fast pace of change took some by surprise.

In these cases, it is the sustained speed/rate of something that matters, not the time it takes to occur. We say that a car is “fast,” for example, because this reflects its potential for sustained speed, whereas “quick” would imply a brief action.

An important exception to this is “fast food,” which is so called because it is made quickly. It does not usually move fast unless you throw it across the room, which is widely considered impolite.

If anything, eating it will probably slow you down.

In addition, we can use “fast” as an adverb when describing an action:

You always drive too fast.

“Fast” has some other meanings, too, such as “hard to move” or to abstain from food for a period of time. However, these are much harder to confuse with the word “quick”!

Quick or Fast?

These words are often interchangeable when referring to something that happens at speed. But this is not always the case. The key to avoiding errors is therefore considering whether time is relevant.

If you’re describing something that happens in a short time, it will typically be “quick.” But if it is something that is capable of moving fast or that occurs at a high rate, the correct word will be “fast.”

Quick = Happening at speed or in a short time

Fast = Happening at a high speed or rate, or capable of moving at speed

Comments (8)
30th November 2021 at 20:30
Ironically there is a typo on this page. The key in these cases is that it [IS] about the sustained speed/rate of something, not the time it takes to occur.
    1st December 2021 at 11:23
    Hi, Jordyn. The error is fixed now. Thanks for pointing it out.
6th March 2022 at 17:42
"An important exception to this is 'fast food,' which is so called because it is made quickly. It does not usually move fast unless you throw it across the room, which is widely considered impolite." - Loved this part, it has a bit of Adams/Pratchett vibe :) "'Fast' has some other meanings, too, such as 'hard to move'" - while I was still learning English, the phrase "to stand fast" confused me to no end... How can you *stand*, *fast*? :)
    7th March 2022 at 10:51
    Hi, Ivan. Thanks for your kind comments! On the issue of "to stand fast" and similar, it might help to know that this meaning is the older one. While the etymology isn't 100% clear, one possibly connection is that, in older Scandinavian languages, fast was an intensifier in some contexts, a bit like how "hard" is used in English today. So to "run fast" was the same as to "run hard," which might have given rise to the sense of speediness we know today. Another possibility is that it drew on the idea of sticking firmly to something in a chase (i.e., that to run "fast" was to stick closely to the thing you were pursuing). Ultimately, whatever the route, most definitions of "fast" seem to have roots in the sense of something being strong, solid, or firm, even if these qualities are quite far removed from the modern meaning of "fast" to mean "quick."
    27th December 2022 at 10:22
    > it will be typically be “quick.” There is an extra "be" that should be removed.
      30th December 2022 at 12:21
      Hi, Mike. Thank you very much for spotting that! We'll get that error sorted.
Reza Foyouzi
18th February 2023 at 13:19
Thank you for the elaborate explanation. Is there any exception to the rule that fast and quickly may be used in sentences in which the rules given here contradict their uses? And, how can we know that they are interchangeable in some sentences? Any tricks?
    27th February 2023 at 16:58
    Hi, Reza. Thanks for your questions! “Fast” and “quick” are interchangeable when they act as an adjective that refers to something happening at speed, as described above; “John was always quick to respond” and “John was always fast to respond” can be used to mean the same thing. In most other cases, you can use the rules we outlined in our summary above: “quick” describing something happening in a short space of time, and “fast” describing something moving at high speed. I’m not aware of many exceptions, aside from the one mentioned above about “fast food,” but as always with any grammar rule in English, I’m sure there are probably more! If you stick to the guide here though, you’ll be safe.

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