PHP Add 4 hours to date

Question

I'm trying to add four hours to a date but the resultant time is incorrect

$date = $dates[0] < $dates[1] ? $dates[1] : $dates[0];
$new_date = date("Y-m-d H:i:s", strtotime('+4 hours', $date));
echo $date;
echo "<br/>". $new_date;

The result i'm getting is

2015-09-17 09:36:18

1969-12-31 20:33:35

The first date is correct but the second isn't, it should be 4 hours ahead of the first

`var_dump(strtotime('+4 hours', $date))` will show a boolean false,which means `$date` is **NOT** unix time stamp. boolean false is integer 0, as far as `date()` is concerned, which'd come out as Jan 1/1970 — Marc B, Sep 17 '15 at 14:53

score 4 · Accepted Answer · edited Jan 06 '22 at 20:20

4

Does this work?

$date = $dates[0] < $dates[1] ? $dates[1] : $dates[0];
$new_date = date("Y-m-d H:i:s", strtotime('+4 hours', strtotime($date)));
echo $date;
echo "<br/>". $new_date;

You were passing $date AS the second argument of strtotime, and it's not a UNIX timestamp (as you said). So with strtotime again, you should convert it in a UNIX timestamp, and then pass it to strtotime.

edited Jan 06 '22 at 20:20

Progrower

363
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answered Sep 17 '15 at 14:53

Zerquix18

769
6
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Could you please emphasis on your improvement? – D4V1D Sep 17 '15 at 14:55

score 2 · Answer 2 · answered Sep 17 '15 at 14:57

Add timestamps to a timestamp, not to a date string.

echo  date("Y-m-d H:i:s", strtotime('+4 hours', strtotime("2015-09-17  09:36:18")));
                                                ^

Fiddle

That is the right syntax. You can simplify it however with

echo  date("Y-m-d H:i:s", strtotime('2015-09-17 09:36:18 +4 hours'));

Fiddle

score 2 · Answer 3 · answered Sep 17 '15 at 14:58

You're using strtotime incorrectly. Its second argument MUSt be a unix timestamp:

php > var_dump(strtotime('+4 hours', 12345));
int(26745)
php > var_dump(strtotime('+4 hours', '2015-09-17 09:36:18'));
PHP Notice:  A non well formed numeric value encountered in php shell code on line 1
int(16415)

Your call should be

php >  var_dump(date('r', strtotime('2015-09-17 09:36:18 + 4 hours')));
                                                        ^^^^^^^^^^^
string(31) "Thu, 17 Sep 2015 13:36:18 -0500"
php >

Ali · Answer 4 · 2015-09-18T09:47:48.213

Both other answers are correct.

Not seeing what you have in your $dates array makes it a bit tricky to give exact answer :) but in the following example i assumed you have a well formatted string date, in which case you need to convert it back to the timestamp using same method (strtotime) before adding what you like into it .

$date = (new DateTime('now'))->format('Y-m-d H:i:s');
$new_date = date('Y-m-d H:i:s', strtotime('+4 hours', strtotime($date)));

echo $date . PHP_EOL . $new_date;

In other word, if your $date array contains UNIX time stamp then your original code should work

$date = (new DateTime('now'))->getTimestamp();
$new_date = date("Y-m-d H:i:s", strtotime('+4 hours', $date));

PHP Add 4 hours to date

4 Answers4