Getting a timestamp for today at midnight?

Question

How would I go about getting a timestamp in php for today at midnight. Say it's monday 5PM and I want the Timestamp for Monday(today) at midnight(12 am) which already has happened.

Thank you

Solution 1

$timestamp = strtotime('today midnight');

or via a DateTime:

$date = new DateTime('today midnight');
// or: $date = date_create('today midnight');
$timestamp = $date->getTimestamp();

and then perhaps immutable:

$midnight = new DateTimeImmutable('today midnight');
// or: $midnight = date_create_immutable('today midnight');
$timestampOfMidnight = $midnight->getTimestamp();

1. That is in the default timezone.
2. Spoiler: just "midnight" or or just "today" return the same.
3. Add a timezone, e.g. "UTC today", to have it, always.
4. Spoiler #2: UTC greeting style: "midnightZ"
5. History: midnight is since PHP 5.1.2 (Jan 2006), today since PHP 4.3.1 (Feb 2003)

More examples:

given the time UTC 2020-01-01 00:00:00:

UTC time is ............: [red   ] 1577836800

when calling strtotime($), results are:

today midnight .........: [pink  ] 1577833200
midnight ...............: [pink  ] 1577833200
today ..................: [pink  ] 1577833200
tomorrow ...............: [green ] 1577919600
UTC today ..............: [red   ] 1577836800
today Z ................: [red   ] 1577836800
Asia/Shanghai today ....: [lime  ] 1577808000
Asia/Shanghai ..........: [blue  ] 1577811600
HKST today .............: [copper] 1577804400

Online Demo: https://3v4l.org/KWFJl

---

PHP Documentation:

• On the Relative Formats page, see the Day-based Notations table. These formats are for strtotime(), DateTime and date_create().

• You might want to take a look what more PHP has to offer: https://php.net/datetime - the entry page to date-time related functions and objects in PHP with links to other, date-time related extensions.

---

NOTE: While "midnight" being technically between two days, here it is "today" (start of day) with PHPs' strtotime.

Discussion:

In so far, the answer strtotime("today midnight") or strtotime("midnight today") is a complete and well sounding answer for PHP, it may appear a bit verbose as strtotime("midnight") and strtotime("today") return the same result.

But even being more verbose not always instantly answers the question if it is about the Midnight for start of day or the Midnight for end of day even today is given as context. We may think about the start of day when reading "today midnight", but this is an assumption and not precise and perhaps can't be. Wikipedia:

Though there is no global unanimity on the issue, most often midnight is considered the start of a new day and is associated with the hour 00:00.

Compare with this programming question:

• Given midnight is a time transition
• When asking for a single UNIX timestamp
• Then there is no answer

(it would be between two UNIX timestamps, so you would take two timestamps and describe what the two mean and this would not answer the question as it asks for a single timestamp).

This is not easy to completely resolve because of this mismatch and by how UNIX Time references date/time.

Lets take the well known, digital 24-hour clock with hours and minutes and express midnight (is it more precise?):

$midnight = strtotime("today 00:00");

or for end of day:

$midnight = strtotime("today 24:00");

(NOTE: shown as start of next day)

Or the 12-hour clock, it can also be used to give the UNIX Timestamp of today at midnight:

$midnight = strtotime("12:00 a.m.");

(NOTE: the "12 midnight" notation is not supported by strtotime())

The confusion that can result of a transition time like Midnight to map on a clock may even become more visible with the 12-hour clock as similar to "midnight" the midday (not available in PHP as a relative date/time format but "noon") is technically between again (now between two full dates at noon, or between the first and the second half of a day).

As this adds up, the code is likely not well received over a 24 hour clock or just writing out "today midnight".

Your mileage may vary.

This is kind of aligned with clock time. From Wikipedia Midnight:

"Midnight is the transition time from one day to the next – the moment when the date changes, on the local official clock time for any particular jurisdiction. By clock time, midnight is the opposite of noon, differing from it by 12 hours. [bold by me]"

and from the Wikipedia 12-hour clock:

"It is not always clear what times "12:00 a.m." and "12:00 p.m." denote. From the Latin words meridies (midday), ante (before) and post (after), the term ante meridiem (a.m.) means before midday and post meridiem (p.m.) means after midday. Since "noon" (midday, meridies (m.)) is neither before nor after itself, the terms a.m. and p.m. do not apply. Although "12 m." was suggested as a way to indicate noon, this is seldom done and also does not resolve the question of how to indicate midnight."

Solution 2

I think that you should use the new PHP DateTime object as it has no issues doing dates beyond the 32 bit restrictions that strtotime() has. Here's an example of how you would get today's date at midnight.

$today = new DateTime();
$today->setTime(0,0);

Or if you're using PHP 5.4 or later you can do it this way:

$today = (new DateTime())->setTime(0,0);

Then you can use the echo $today->format('Y-m-d'); to get the format you want your object output as.

PHP DateTime Object

Solution 3

Today at midnight. Easy.

$stamp = mktime(0, 0, 0);

Solution 4

You are looking to calculate the time of the most recent celestial event where the sun has passed directly below your feet, adjusted for local conventions of marking high noon and also potentially adjusting so that people have enough daylight left after returning home from work, and for other political considerations.

Daunting right? Actually this is a common problem but the complete answer is location-dependent:

$zone = new \DateTimeZone('America/New_York'); // Or your own definition of “here”
$todayStart = new \DateTime('today midnight', $zone);
$timestamp = $todayStart->getTimestamp();

Potential definitions of “here” are listed at https://secure.php.net/manual/en/timezones.php

Solution 5

Updated Answer in 19 April, 2020

Simply we can do this:

$today = date('Y-m-d 00:00:00');

View more solutions

Comments

[wesside]

timestamp? That's just a date.

[SamHuckaby]

Is there a particular format that the OP asked for? If so, I would be happy to modify my post to return any format they would like.

[wesside]

completely overlooked strtotime(), mind was so focused on the date function. Apologies.

[hakre]

@SamHuckaby: It is even more easy: $timestamp = strtotime('today'); is midnight. But pssst the one above looks cooler as an answer to the question ;)

[Happy Coder]

I actually need to get start of today and midnight of today. How can I find start of today I mean for 00:00:00

[hakre]

@AlwinAugustin: You should consider to differ your wording. Midnight is technically between two days. So there is somewhat "no today any longer". Also: Midgnight of today (per definition) is (right before) the start of today. You probably mean the next midnight after today noon.

[Happy Coder]

yeah actually what I need is 00:00:00 of today and 23:59:59 of today

[Martijn]

I also prefer using the new DateTime object. If you combine this answer with @hakr's you get: new DateTime('today midnight'), which makes the intention more clear (but this is of course a matter of taste).

[NobleUplift]

I'm doing ORM SQL work and I had to use the DateTime object for comparisons. This is exactly what I was looking for. +1

[Boaz Rymland]

For 'midnight of current day' use the recipe given above. For midnight of 'this day' (the one to come, today at midnight), just add 60 * 60 *24 to the previous value... :-)

[ProgZi]

May be $today = new DateTime('today')

[Christopher K.]

Also useful if you are using Carbon, which inherits from DateTime. Thus, you can also do new Carbon('today midnight') and then you can use all the Carbon stuff like ->subDays(6). See carbon.nesbot.com

[Christopher K.]

Regarding the 32 bit restriction: The PHP docu for strtotime states: "For 64-bit versions of PHP, the valid range of a timestamp is effectively infinite, as 64 bits can represent approximately 293 billion years in either direction." So it only applies to 32bit php.

[mae]

Keep in mind this will produce the midnight of your PHP server's timezone, not UTC+0! To get UTC+0 you can use strtotime('today+00:00').

[hakre]

@BoazRymland: No need to do (incorrect) seconds for a day calculation for that, just use strtotime('tomorrow').

[hakre]

@mae nice, there are even alternative ways like today+0, today Z, UTC today, Asia/Shanghai today or HKST today. I have problems to find this in the PHP docs specifically, 3v4l.org link which was missing so far: 3v4l.org/amfGc

[hakre]

Like strtotime('America/New_York today midnight');? - 3v4l.org/I85qD

[WoodrowShigeru]

For anyone who was wondering, calling this at the moment of midnight gets the current time (no difference) – not yesterday's midnight. These are all the same (today): strtotime('2020-08-23 00:00'); strtotime('midnight'); strtotime('midnight', strtotime('2020-08-23 00:00'));