I saw that when we are saying that something is available at all days of the week at all hours, we say its available 24 x 7, and when its available every day (or, every week) of the year at all hours, we call its there 24 x 7 x 365

I know that 24 x 7 clearly denotes the number of hours in a week, but why do say 24 x 7 x 365 rather than saying 24 x 365? Clearly, both have a different answer after multiplication, and so that denotation of the number of hours is absolutely different.

Is there any reason for this?

  • Somewhat related (not dupe): english.stackexchange.com/q/351730/13804
    – cobaltduck
    Jan 18, 2018 at 12:38
  • 3
    24x7x52 would be more logical, but the use you describe has, sadly, been established.
    – Davo
    Jan 18, 2018 at 12:38
  • @Davo That's what I too was thinking! Jan 18, 2018 at 12:38
  • 3
    Yay! We get a day off every four years!
    – Mitch
    Jan 18, 2018 at 13:09
  • 3
    I'm voting to close this question as off-topic because it's not about English Jan 18, 2018 at 14:06

5 Answers 5


There are several variants of this, "24/7", "24-7", "24/365", "24X365" and so on.

Those with a multiplication are clearly depending on the fact that e.g. 24×7 will indeed, if calculated, give the number of hours in a week.

The main point of that expression is not to convey 168 nor for "24×365" to convey 8760 (which forgets leap years anyway). It's to convey that information which is also available in the forms which don't use the multiplication symbol, viz that the service, shop, etc. is available at every hour and at every day of the week and/or year.

"24-7-365" conveys availability at every hour and at every day of the week and at every day of the year. The "7" is redundant when we have the "365" but it relates to a different concern: It might be more important to me that a service is available on Saturdays than that it is available on Christmas, so I might care about the "7" more than I do about the "365" even though the latter logically entails the former.

The mathematically incorrect "24×7×365" is just a merging of that with the forms where the arithmetic actually does work, because similar common expressions will always end up being merged, especially when written quickly.


The expression is written several ways: 24-7-365, 24/7/365, or 24x7x365. The last one is not a mathematical formula indicating multiplication, but merely a variation in punctuation. The 365 is an intensifier of the far more common 24/7, since "24 hours a day, 7 days a week" covers everything, though perhaps it assures the reader that the service is also available on legal holidays. Without the 24/7, 24x365, however, does look like a multiplication problem, thus won't likely replace 24-7-365 any time soon.


This has nothing to do with multiplication, this is an English language abbreviation for measurements.

Think of a piece of wood that is 10 inches high and 4 inches wide and 2 inches thick. You could describe its size as 10x4x2.

This same approach is also used with measurements of time.

24 x 7 is an abbreviation for 24 hours a day, 7 days a week

24 x 7 x 365 is an abbreviation for 24 hours a day, 7 days a week, 365 days a year

These are abbreviations not formulae.

  • 3
    I think the question was about the redundancy of the "7 days a week" in the 24x7x365 version because the 365 days is every day of the year, which is only possible if you work 7 days a week. Apr 21, 2021 at 20:38
  • Yes but it isn't redundant. 24x7 doesn't say that this applies every day of every week. 24x7 could still mean closed on holidays. 24x7x365 explicitly means not closed on holidays. This is just common use English. It isn't mathematics and it doesn't have to be logical. It just is.
    – bob
    Apr 21, 2021 at 22:06
  • 2
    The 24 x 7 x 365 version does contain redundancy because the 365 directly implies the 7. You can't work a 365 day year without working 7 days a week (as the accepted answer already mentions). Your answer doesn't address why 24 x 365 isn't used instead (when it's logically the same). Apr 21, 2021 at 22:34
  • You can work 24x7 without working 24x7x365. You could take off New Years Day, for example. The 365 emphasises that this happens every day of every week of the year, not just every day of most weeks of the year.
    – bob
    Apr 21, 2021 at 22:35
  • It may well be that x in 24x7x365 should not be interpreted as the multiplication sign (that has already been said in other answers), but that point is not supported by the analogy with stating the size of a piece of wood as 10x4x2, because in that case taking x as the multiplication sign is meaningful (the volume of such a piece is the result of multiplying the three dimensions).
    – jsw29
    Apr 21, 2021 at 22:41

I've never seen 27/7-365 or anything like it. What I have seen (maybe once or twice) is 24/7/52, which makes sense to me: 24 hours a day, 7 days a week, 52 weeks a year.

  • 52 full weeks in a year, adds up to only 364 days. All years actually straddle 53 weeks.
    – Steve
    Dec 29, 2020 at 22:35
  • By this reckoning you would be writing 24/7:365-366 (or -365.24) 52 carries the "all-year" meaning well enough, I think Dec 30, 2020 at 23:07

I know that 24 x 7 clearly denotes the number of hours in a week.

It doesn’t.

We actually say "[It is available] twenty-four, seven."

“Twenty-four, seven” is a contraction of “[for/all] twenty-four hours, seven days a week.”

Seven days a week = every day. (adverbial phrase)

Every day includes every day of a year, decade, century and millennium, etc. The 365 (pron. “three-six-five”) is mere emphasis and adds nothing.

  • 1
    I don't agree that 365 "adds nothing". It was typical in the past for an operation to be regularly closed at certain hours of the day, on certain weekdays, and on certain days of the year (Christmas Day, for example, which has been a non-working day since time immemorial, regardless of the day of the week it falls). Each number makes it emphatically clear that no such closing times exist - not the daily closed hours, not the weekly closed days, and not the yearly closed days.
    – Steve
    Dec 29, 2020 at 22:33
  • @Steve If it is not available on public holidays, then it is not available 24/7.
    – Greybeard
    Dec 30, 2020 at 11:16
  • I'm afraid that doesn't reflect typical understandings. At any rate, my point is not so much to establish the justification, only to clarify what role the "365" component is actually performing - it makes clear that there are no exceptions to the 24 hour principle across the year, just as "7" makes clear that there are no exceptions across the week (since by your logic, a shop open 24 hours a day except on Sunday, would not be open 24 hours a day at all, but in conventional understanding this means the shop is indeed open 24 hours a day, but only on 6 days of the week).
    – Steve
    Dec 30, 2020 at 12:13

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