strtotime

(PHP 4, PHP 5, PHP 7, PHP 8)

strtotime 英文形式の日付を Unix タイムスタンプに変換する

説明

strtotime(string $datetime, ?int $baseTimestamp = null): int|false

この関数は英語の書式での日付を含む文字列が指定されることを期待しており、 その書式を Unix タイムスタンプ (1970 年 1 月 1 日 00:00:00 UTC からの経過秒数) に変換しようとします。 baseTimestamp が指定された場合は、そのタイムスタンプを基準とした相対時刻のタイムスタンプに変換します。 baseTimestamp が指定されていない場合は、現在時刻を基準とした相対時刻のタイムスタンプに変換します。 パースされる日付を含む文字列の書式は、 サポートする日付と時刻の書式 で定義されており、考慮すべき微妙な点がいくつかあります。 サポートする日付と時刻の書式について、読んでおくことを強く推奨します。

警告

この関数が返す Unixタイムスタンプ は、タイムゾーンの情報を含んでいません。 日付/時刻の情報を含めて計算するには、 より多くの機能がある DateTimeImmutable を使うべきです。

この関数の各パラメータでは、パラメータ内でタイムゾーンを指定しない限りはデフォルトのタイムゾーンを使います。 意図的にそうする場合は別として、パラメータごとにタイムゾーンを変えてしまったりしないように気をつけましょう。 デフォルトのタイムゾーンを定義する方法については date_default_timezone_get() を参照ください。

パラメータ

datetime

日付/時刻 文字列。有効な書式については 日付と時刻の書式 で説明しています。

baseTimestamp

返される値を計算するために使用されるタイムスタンプ。

戻り値

成功時はタイムスタンプ、そうでなければ false を返します。

エラー / 例外

すべての日付/時刻関数は、 有効なタイムゾーンが設定されていない場合に E_WARNING を発生させます。 date_default_timezone_set() も参照ください。

変更履歴

バージョン 説明
8.0.0 baseTimestamp は、nullable になりました。

例1 strtotime() の例

<?php
echo strtotime("now"), "\n";
echo 
strtotime("10 September 2000"), "\n";
echo 
strtotime("+1 day"), "\n";
echo 
strtotime("+1 week"), "\n";
echo 
strtotime("+1 week 2 days 4 hours 2 seconds"), "\n";
echo 
strtotime("next Thursday"), "\n";
echo 
strtotime("last Monday"), "\n";
?>

例2 失敗のチェック

<?php
$str 
'Not Good';

if ((
$timestamp strtotime($str)) === false) {
    echo 
"The string ($str) is bogus";
} else {
    echo 
"$str == " date('l dS \o\f F Y h:i:s A'$timestamp);
}
?>

注意

注意:

"相対的な" 日付とは、 日付/時刻の一部の情報が与えられていないということでもあります。 与えられていない情報は baseTimestamp から取得されます。 つまり、2022年5月31日 (31st of May 2022) に strtotime('February') を実行すると、 31 February 2022 と解釈されて日付がオーバーフローし、 3 March になります(うるう年の場合、2 March になります)。 strtotime('1 February')strtotime('first day of February') を使うことで、この問題は回避できます。

注意:

年を 2 桁の数値で指定した場合、その値が 00-69 なら 2000-2069 に、 70-99 なら 1970-1999 にそれぞれ変換されます。 32 ビットシステム上での相違点 (2038-01-19 03:14:07 までの日付しか表せない) については以下の注意を参照ください。

注意:

タイムスタンプの有効な範囲は、通常、Fri, 13 Dec 1901 20:45:54 UTC から Tue, 19 Jan 2038 03:14:07 UTC までです (これらは、32 ビット符号付整数の最大及び最小に一致します)。

64 ビット版の PHP では、タイムスタンプの有効範囲は事実上無制限です。 というのも、64 ビットでは過去側も未来側も約 2930 億年を表せるからです。

注意:

この関数を使って日付の足し算や引き算を行うことはおすすめできません。 DateTime::add()DateTime::sub() を使いましょう。

参考

add a note

User Contributed Notes 19 notes

up
122
kumar AT swatantra.info Swatantra Kumar
9 years ago
The "+1 month" issue with strtotime
===================================
As noted in several blogs, strtotime() solves the "+1 month" ("next month") issue on days that do not exist in the subsequent month differently than other implementations like for example MySQL.

<?php
echo date( "Y-m-d", strtotime( "2009-01-31 +1 month" ) ); // PHP:  2009-03-03
echo date( "Y-m-d", strtotime( "2009-01-31 +2 month" ) ); // PHP:  2009-03-31
?>

<?php
SELECT DATE_ADD
( '2009-01-31', INTERVAL 1 MONTH ); // MySQL:  2009-02-28
?>
up
49
cristinawithout
10 years ago
WARNING when using "next month", "last month", "+1 month",  "-1 month" or any combination of +/-X months. It will give non-intuitive results on Jan 30th and 31st.

As described at : http://derickrethans.nl/obtaining-the-next-month-in-php.html

<?php
$d
= new DateTime( '2010-01-31' );
$d->modify( 'next month' );
echo
$d->format( 'F' ), "\n";
?>

In the above, using "next month" on January 31 will output "March" even though you might want it to output "February". ("+1 month" will give the same result. "last month", "-1 month" are similarly affected, but the results would be seen at beginning of March.)

The way to get what people would generally be looking for when they say "next month" even on Jan 30 and Jan 31 is to use "first day of next month":

<?php
$d
= new DateTime( '2010-01-08' );
$d->modify( 'first day of next month' );
echo
$d->format( 'F' ), "\n";
?>

<?php
$d
= new DateTime( '2010-01-08' );
$d->modify( 'first day of +1 month' );
echo
$d->format( 'F' ), "\n";
?>
up
16
joe at strtotime dot co dot uk
7 years ago
A useful testing tool for strtotime() and unix timestamp conversion:
http://strtotime.co.uk/
up
19
michal dot kocarek at brainbox dot cz
13 years ago
strtotime() also returns time by year and weeknumber. (I use PHP 5.2.8, PHP 4 does not support it.) Queries can be in two forms:
- "yyyyWww", where yyyy is 4-digit year, W is literal and ww is 2-digit weeknumber. Returns timestamp for first day of week (for me Monday)
- "yyyy-Www-d", where yyyy is 4-digit year, W is literal, ww is 2-digit weeknumber and dd is day of week (1 for Monday, 7 for Sunday)

<?php
// Get timestamp of 32nd week in 2009.
strtotime('2009W32'); // returns timestamp for Mon, 03 Aug 2009 00:00:00
// Weeknumbers < 10 must be padded with zero:
strtotime('2009W01'); // returns timestamp for Mon, 29 Dec 2008 00:00:00
// strtotime('2009W1'); // error! returns false

// See timestamp for Tuesday in 5th week of 2008
strtotime('2008-W05-2'); // returns timestamp for Tue, 29 Jan 2008 00:00:00
?>

Weeknumbers are (probably) computed according to ISO-8601 specification, so doing date('W') on given timestamps should return passed weeknumber.
up
7
mirco dot babin at gmail dot com
3 years ago
One important thing you should remember is that the timestamp value returned by time() is time-zone agnostic and gets the number of seconds since 1 January 1970 at 00:00:00 UTC. This means that at a particular point in time, this function will return the same value in the US, Europe, India, Japan, ...

strtotime() will convert a string WITHOUT a timezone indication as if the string is a time in the default timezone ( date_default_timezone_set() ). So converting a UTC time like '2018-12-06T09:04:55' with strtotime() actually yields a wrong result. In this case use:

<?php
function UTCdatestringToTime($utcdatestring)
{
   
$tz = date_default_timezone_get();
   
date_default_timezone_set('UTC');

   
$result = strtotime($utcdatestring);

   
date_default_timezone_set($tz);
    return
$result;
}
?>

Test:
<?php
$tz
= 'Europe/Amsterdam';
$utctime = '2018-12-06T09:04:55';

if (!
date_default_timezone_set($tz)) {
   
WriteLine('Setting default timezone to ' . $tz . ' failed');
    die;
}

WriteLine();
WriteLine('Default timezone set to ' . $tz);
WriteLine('UTC time: ' . $utctime);
WriteLine();

WriteLine('[ UTCdatestringToTime ]');
$phptime = UTCdatestringToTime($utctime);
WriteLine('PHP time: ' . $phptime);
WriteTime($phptime, true);
WriteTime($phptime, false);
WriteLine();

WriteLine('-------------------------------------------------------------------------------');
WriteLine('[ strtotime($utctime) - Converts $utctime as if it was in timezone ' . $tz . ' because the string has no timezone specification ]');
$phptime = strtotime($utctime); //Seconds since the unix epoch
WriteLine('PHP time: ' . $phptime);
WriteTime($phptime, true);
WriteTime($phptime, false);

function
WriteLine($text = '')
{
    echo
$text . "\r\n";
}

function
WriteTime($time, bool $asUTC)
{
   
$tz = date_default_timezone_get();
    if (
$asUTC) date_default_timezone_set('UTC');
   
   
WriteLine('--> (' . date_default_timezone_get() . ') ' . date('Y-m-d H:i:s', $time));
   
    if (
$asUTC) date_default_timezone_set($tz);
}
?>

Test output:
<?php

Default timezone set to Europe/Amsterdam
UTC time
: 2018-12-06T09:04:55

[ UTCdatestringToTime ]
PHP time: 1544087095
--> (UTC) 2018-12-06 09:04:55
--> (Europe/Amsterdam) 2018-12-06 10:04:55

-------------------------------------------------------------------------------
[
strtotime($utctime) - Converts $utctime as if it was in timezone Europe/Amsterdam because the string has no timezone specification ]
PHP time: 1544083495
--> (UTC) 2018-12-06 08:04:55
--> (Europe/Amsterdam) 2018-12-06 09:04:55
*/
?>
up
6
Steve GS
5 years ago
The difference between 'today' and 'now' is the former strips off the time (setting it to 00:00, ie. midnight just past), and the latter includes the time - assuming UTC unless specified otherwise.

I run a theatre's website.  Obviously, I need to ensure shows that have already happened do not appear on web pages, so I use something on the lines of:

    $listIt = (strtotime($end_date) >= strtotime('today') ? 1 : 0);

where $end_date is the final date in a show series.  So if tonight's show is the last, it will stay on the web page until 00:00 tomorrow.

I don't normally include performance times in the date field because some shows have matinées, others don't - so I use a free-form performance time field in the CMS instead (where even 'Time: TBD' is allowed).  [The only instance where I DO include the time is when there are two different shows on the same day, to ensure they appear in chronological order.]

So strtotime($end_date) will always return the timestamp at 00:00 that day.  If I instead used:

    $listIt = (strtotime($end_date) >= strtotime('now') ? 1 : 0);

the function would return $listIt = 0 at all times today - something I don't want.

HTH
up
10
shannon
4 years ago
I tried using sams most popular example but got incorrect results.

Incorrect:
<?php
echo date("jS F, Y", strtotime("11.12.10"));
// outputs 10th December, 2011

echo date("jS F, Y", strtotime("11/12/10"));
// outputs 12th November, 2010

echo date("jS F, Y", strtotime("11-12-10"));
// outputs 11th December, 2010 
?>

Then I read the notes which said:
if the separator is a slash (/), then the American m/d/y is assumed; whereas if the separator is a dash (-) or a dot (.), then the European d-m-y format is assumed. ***If, however, the year is given in a two digit format and the separator is a dash (-), the date string is parsed as y-m-d.***

Therefore, the above code does not work on 2 digit years - only 4 digit years
up
10
me at will morgan dot co dot you kay
9 years ago
For negative UNIX timestamps, strtotime seems to return the literal you passed in, or it may try to deduct the number of seconds from today's date.

To work around this behaviour, it appears that the same behaviour as described in the DateTime classes applies:

http://php.net/manual/en/datetime.construct.php

Specifically this line here (in the EN manual):

> The $timezone parameter and the current timezone are ignored when the $time parameter either is a UNIX timestamp (e.g. @946684800) or specifies a timezone (e.g. 2010-01-28T15:00:00+02:00).

Therefore strtotime('@-1000') returns 1000 seconds before the epoch.

Hope this helps.
up
2
marlonsouza90 at hotmail dot com
2 years ago
strtotime();

exemplo strtotime(date("Y-m-d") . "+1month");

A strtotime também funciona quando concatenamos strings,
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4
chris at teamsiems dot com
12 years ago
It took me a while to notice that strtotime starts searching from just after midnight of the first day of the month. So, if the month starts on the day you search for, the first day of the search is actually the next occurrence of the day.

In my case, when I look for first Tuesday of the current month, I need to include a check to see if the month starts on a Tuesday.

<?php
if (date("l", strtotime("$thisMonth $thisYear"))=='Tuesday') {
  echo
"<p>This month starts on a Tuesday. Use \"$thisMonth $thisYear\" to check for first Tuesday.</p>\n";
} else {
  echo
"<p>This month does not start on a Tuesday. Use \"first tuesday $thisMonth $thisYear\" to check for first Tuesday.</p>\n";
}
?>
up
5
kyle at frozenonline dot com
18 years ago
I was having trouble parsing Apache log files that consisted of a time entry (denoted by %t for Apache configuration). An example Apache-date looks like: [21/Dec/2003:00:52:39 -0500]

Apache claims this to be a 'standard english format' time. strtotime() feels otherwise.

I came up with this function to assist in parsing this peculiar format.

<?php
function from_apachedate($date)
{
        list(
$d, $M, $y, $h, $m, $s, $z) = sscanf($date, "[%2d/%3s/%4d:%2d:%2d:%2d %5s]");
        return
strtotime("$d $M $y $h:$m:$s $z");
}
?>

Hope it helps anyone else seeking such a conversion.
up
3
Michael Muryn (MickoZ)
11 years ago
[red.: This is a bug, and should be fixed. I have file an issue]

This comment apply to PHP5+

We can now do thing like this with strtotime:
<?php
$weekMondayTime
= strtotime('Monday this week');
?>
However this works based on a week starting Sunday.  I do not know if we can tweak this PHP behavior, anyone know?

If you want the timestamp of the start of the ISO Week (i.e. on Monday) as defined by ISO 8601, you can use this one liner:
<?php
$isoWeekStartTime
= strtotime(date('o-\\WW')); // {isoYear}-W{isoWeekNumber}
?>

You can also find out the start of week of any time and format it into an ISO date with another one liner like this:
<?php
$isoWeekStartDate
= date('Y-m-d', strtotime(date('o-\\WW', $time)));
?>

For more information about ISO-8601 and ISO week date:
http://en.wikipedia.org/wiki/ISO_8601#Week_dates
http://en.wikipedia.org/wiki/ISO_week_date
up
1
a dot fruchi at bit-runners dot com
11 years ago
If you want to confront a date stored into mysql as a date field (not a datetime) and a date specified by a literal string, be sure to add "midnight" to the literal string, otherwise they won't match:

<?php
//I.E.: today is 17/02/2011

echo strtotime('2011-01-01'); //1293836400
echo strtotime('first day of last month'); //1293888128 Note: it's different from the previous one, since it computes also the seconds passed from midnight!!! So this one is always greater than simple '2011-01-01'
echo strtotime('midnight first day of last monty');//1293836400 Note: it's the same as '2011-01-01'

?>
up
0
Black Hat Rocker
1 year ago
*The case 30/11/-0001*
With the following note, I will report a particular behaviour of function strtotime() I want to call it «The case 30/11/-0001».  It is very common and known but never reported  here. Passing the input parameter '0000-00-00' to the function it returns a wrong and not supported timestamp value. It can be seen with these statement

<?php echo date('d/m/Y', strtotime('0000-00-00')); // returns 30/11/-0001  ?>

It seems there's no way to avoid that, but it is possibile to do workaround with if/3operator clausole simply as follow

<?php strcmp($date "0000-00-00")? date('d/m/Y', strtotime($date) ) :  date('d/m/Y') ?>

Otherwise a simple way is to avoid to store to the DB the value '0000-00-00' and insert a default data value (i.e. with the mySQL function NOW() which sets the date on today's date)
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-2
phpmanual at NOSPAM dot headbank dot co dot uk
2 months ago
For those still using php versions < 8.0.0, it may help to know that explicitly supplying the 2nd argument $baseTime as NULL does *not* have the same effect as omitting it.

<?php
function adjustedTime($adjustment, $baseTime = null) {
  echo
date('Y-m-d H:i:s', strtotime($adjustment, $baseTime));
}

adjustTime('+1 day');

//1970-01-02 01:00:00
?>
Supplying NULL is equivalent to supplying int(0).

So if you wrap strtotime() in this manner with a nullable $baseTime, make sure in your code to inspect $baseTime and supply time() instead of NULL, or call strtotime() without it in that case.
up
0
vlad dot savitsky at gmail dot com
4 years ago
Little bit unexpected behaviour for me. Small integers treats like time.
strtotime(0) => false,
strtotime(1) => false,
strtotime(12) => false,
strtotime(123) => false,
strtotime(1234) => 1528194840, //Time '12:34'
strtotime(12345) => false,
strtotime(123456) => 1528194896, // Time '12:34:56'
strtotime(1234567) => false,
strtotime(12345678) => false,
strtotime(123456789) => false,
up
-1
marcodemaio at vanylla dot it
11 years ago
NOTE: strtotime returns different values when the Week day does not match the date.

Simple example:

<?php
$d1
= strtotime("26 Oct 0010 12:00:00 +0100");
$d2 = strtotime("Tue, 26 Oct 0010 12:00:00 +0100");
$d3 = strtotime("Sun, 26 Oct 0010 12:00:00 +0100"); //But Oct 26 is a Tuesday, NOT a Sunday.

echo $d1; //ok 1288090800 that is "26 Ott 2010 - 11:00";
echo $d2; //ok 1288090800 that is "26 Ott 2010 - 11:00";
echo $d3; //WRONG! 1288522800 that is "31 Ott 2010 - 11:00";
?>

Sometime I found RSS feeds that contains week days that do not match the date.

A possible solution is to remove useless week day before passing the date string into strtotime, example:

<?php
   $date_string
= "Sun, 26 Oct 0010 12:00:00 +0100";
   if( (
$comma_pos = strpos($date_string, ',')) !== FALSE )
     
$date_string = substr($date_string, $comma_pos + 1);
  
$d3 = strtotime($date_string);
?>
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-2
fuhrysteve at gmail dot com
13 years ago
Here's a hack to make this work for MS SQL's datetime junk, since strtotime() has issues with fractional seconds.

<?php

$MSSQLdatetime
= "Feb  7 2009 09:48:06:697PM";
$newDatetime = preg_replace('/:[0-9][0-9][0-9]/','',$MSSQLdatetime);
$time = strtotime($newDatetime);
echo
$time."\n";

?>
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-5
Sui Dream
4 years ago
It was really pazzling to me to read about parsing a string into a Unix timestamp relative to both January 1 1970 00:00:00 UTC and the second parameter. Maybe it worth noting that the second parameter is for relative dates (like "+1 day").
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