: Why is "29030400" seconds used as a common value for cache expiration? I noticed that 29030400 is used very often in the Expires directives for static files. Google recommends to cache this
I noticed that 29030400 is used very often in the Expires directives for static files.
Google recommends to cache this kind of files up to 1 year (1 month at least).
I did the math: 29030400 seconds = 336 days
That is about 1 year minus 1 month, so it perfectly falls in the recommended interval, but the question is why exactly 29030400? And not 31536000 seconds = 365 days for example? Just a blind copy/paste of a value that was set randomly in the old days? Or does it have another explanation?
More posts by @Voss4911412
2 Comments
Sorted by latest first Latest Oldest Best
Unor is correct.
It's like finding 2419200 seconds in a 4 week month then multiplying by 12 for a year 29030400.
However as you mention, that is not very accurate as many months have 31 days, 5 weeks, etc.
I provide an additional answer (even though the correct answer has been provided) simply to provide the exact seconds for a "gregorian year" which also includes those 5 week months, 28 days in February, etc. In case anyone needs that number.
There are 31556952 seconds in 1 gregorian year.
If you want an exact year in your cache, this may be the number you are looking to use on your cache expirations. :)
It might come from
60 * 60 * 24 * 7 * 4 * 12 = 29030400
where each month consists of exactly 4 weeks.
Terms of Use Create Support ticket Your support tickets Stock Market News! © vmapp.org2024 All Rights reserved.