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 '18 at 12:38
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    24x7x52 would be more logical, but the use you describe has, sadly, been established. – Davo Jan 18 '18 at 12:38
  • @Davo That's what I too was thinking! – Mrigank Pawagi Jan 18 '18 at 12:38
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    Yay! We get a day off every four years! – Mitch Jan 18 '18 at 13:09
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    I'm voting to close this question as off-topic because it's not about English – FumbleFingers Jan 18 '18 at 14:06

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.


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 '20 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 – george storm Dec 30 '20 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.

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    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 '20 at 22:33
  • @Steve If it is not available on public holidays, then it is not available 24/7. – Greybeard Dec 30 '20 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 '20 at 12:13

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