# Diff Between 2 Dates

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I am trying to find the difference between 2 dates. The problem that I am having is that all
routines in the PHP Manual and all of the scripts I have seen on the Internet only allow a date as
old as 1970. I am trying to find the age of a person in months so 1970 is not far back enough. Does
anyone know of a script where 1970 is not a restriction?

Mike

## Re: Diff Between 2 Dates

Mike wrote:

Does the server run Linux or Windows?

--
Carl Vondrick
www.carlsoft.net
usenet [at] carlsoft [dot] net

## Re: Diff Between 2 Dates

Mike wrote:

Have a look at the calendar extension:

http://www.php.net/calendar

JW

## Re: Diff Between 2 Dates

Mike wrote:

The solution is quite simple. This is how people do it in their heads.
First, substract the year the person is born from the current year.
Then, check whether the person has already celebrated his/her birthday
this year.  If not--substract one.

Here's an implementation:

function age(\$year, \$month, \$day) {
\$now_ts = time();
\$now_a = getdate(\$now_ts);
\$age = \$now_a['year'] - \$year;
\$bday_ts = mktime(0, 0, 0, \$month, \$day, \$now_a['year']);
if(\$now_ts < \$bday_ts) {
\$age--;
}
return \$age;
}

## Re: Diff Between 2 Dates

Be aware this works fine for someone's age, but for more precise date
calculations, especially at much older/earlier dates, you will have to
account for all the funny time changes, corrections, and drift that
have taken place (like how they skipped a couple days completely to
make up for lost time).  So i would suggest either reading up on
date/time calculations extensively or finding a good preexisting library

## Re: Diff Between 2 Dates

PHP suffers from the limitations of a UNIX time_t.  I recommend
using MySQL date functions where the allowed range includes the
years 1 thru 9999, which is good enough for most practical uses.

Gordon L. Burditt