添加1年到一个日期

I have a date 01/31/2014, and I need to add a year to it and make it 01/31/2015. I am using

$xdate1 = 01/31/2014;
$xpire = strtotime(date("m/d/Y", strtotime($xdate1)) . " +1 year");

But it is returning 31474800.

Waaaay too complicated. You're doing multiple date<->string conversions, when

php > $x = strtotime('01/31/2014 +1 year');
php > echo date('m/d/Y', $x);
01/31/2015

would do the trick.

There are 2 mistakes here. You are missing the quote sign " when assigning to $xdate1. It should be

$xdate1 = "01/31/2014";

And the second, to get "01/31/2015", use the date function. strtotime returns a timestamp, not a date format. Therefore, use

$xpire = date("m/d/Y", strtotime(date("m/d/Y", strtotime($xdate1)) . " +1 year"));

Another way is below:

<?php
$date = new DateTime('2014-01-31');
$date->add(new DateInterval('P01Y'));
echo $date->getTimestamp();
?>

May I introduce a simple API extension for DateTime with PHP 5.3+:

$xdate1 = Carbon::createFromFormat('m/d/Y', '01/31/2014');
$xpire = $xdate1->addYear(1);

First make $xdate1 as string value like

$xdate1 = '01/31/2014';

then apply date function at it like bellow

$xpire = date('m/d/Y', strtotime($xdate1.' +1 year')); // 01/31/2015