Date Formatting

What Is Date Formatting?

In simple terms: Date formatting turns a date into text in a specific layout — 15/10/2026 for an Indian invoice, Thursday, 15 October 2026 for an event page, or 2026-10-15T14:05:09+05:30 for an API.

Technically: date() (for timestamps) and DateTimeInterface::format() (for date objects) accept a format string in which certain letters are replaced by parts of the date. Both use the same format characters.

date('d/m/Y', $timestamp);       // procedural
$dateTime->format('d/m/Y');      // object-oriented

All examples below use this date:

$d = new DateTimeImmutable('2026-10-15 14:05:09', new DateTimeZone('Asia/Kolkata'));

Format Characters

Day

Week, Month, Year

Time

Time Zone and Full Formats

Characters that are not format letters (spaces, -, /, :, ,) appear in the output unchanged.

Common Formats

<?php
$d = new DateTimeImmutable('2026-10-15 14:05:09', new DateTimeZone('Asia/Kolkata'));

$formats = [
    'd/m/Y',
    'd-m-Y',
    'D, d M Y',
    'l, jS F Y',
    'h:i A',
    'g:i a',
    'Y-m-d H:i:s',
    DATE_ATOM,
    DATE_RFC2822,
];

foreach ($formats as $format) {
    echo str_pad($format, 18) . $d->format($format) . "\n";
}

Output

d/m/Y             15/10/2026
d-m-Y             15-10-2026
D, d M Y          Thu, 15 Oct 2026
l, jS F Y         Thursday, 15th October 2026
h:i A             02:05 PM
g:i a             2:05 pm
Y-m-d H:i:s       2026-10-15 14:05:09
Y-m-d\TH:i:sP     2026-10-15T14:05:09+05:30
D, d M Y H:i:s O  Thu, 15 Oct 2026 14:05:09 +0530

The last two lines show what the predefined constants contain: DATE_ATOM is Y-m-d\TH:i:sP (ISO 8601), and DATE_RFC2822 is D, d M Y H:i:s O.

Which Format for Which Purpose

Displaying dates as 15/10/2026 is fine for Indian users, but never store or exchange dates in local display formats: 05/06/2026 means 5 June in India and 6 May in the United States. ISO 8601 (2026-06-05) is unambiguous and sorts correctly as text.

Escaping Letters in the Format

Every format letter is replaced — even inside words. To print a letter literally, put a backslash before it:

<?php
$d = new DateTimeImmutable('2026-10-15 14:05:09', new DateTimeZone('Asia/Kolkata'));

echo $d->format('l the jS of F') . "\n";
echo $d->format('l \t\h\e jS \o\f F') . "\n";
echo $d->format('\D\a\t\e: d/m/Y') . "\n";

Output

Thursday 3102Asia/Kolkata 15th 2026f October
Thursday the 15th of October
Date: 15/10/2026

In the first line, the word "the" became 3102Asia/Kolkata: t is the number of days in the month (31), h the 12-hour hour (02), and e the time zone identifier. Likewise, o in "of" became the ISO year 2026, while f is not a format letter and stayed unchanged. Escaping each letter (\t\h\e, \o\f) prints the words as written. Use single quotes for format strings, so PHP does not interpret \t as a tab character.

Ordinal Suffixes

<?php
foreach ([1, 2, 3, 4, 11, 12, 13, 21, 22, 23] as $day) {
    $date = new DateTimeImmutable("2026-10-$day");
    echo $date->format('jS') . ' ';
}
echo "\n";

Output

1st 2nd 3rd 4th 11th 12th 13th 21st 22nd 23rd 

S handles the special cases (11th, 12th, 13th) correctly. It produces English suffixes only.

Localized Dates With IntlDateFormatter

date() and format() always produce English names (Thursday, October). For other languages, use IntlDateFormatter from the intl extension, which uses the internationalization data of the ICU library:

<?php
$d = new DateTimeImmutable('2026-10-15 14:05:09', new DateTimeZone('Asia/Kolkata'));

foreach (['en_IN', 'ta_IN', 'hi_IN'] as $locale) {
    $formatter = new IntlDateFormatter(
        $locale,
        IntlDateFormatter::NONE,
        IntlDateFormatter::NONE,
        'Asia/Kolkata',
        IntlDateFormatter::GREGORIAN,
        'd MMMM y'
    );

    echo $locale . ': ' . $formatter->format($d) . "\n";
}

Output (exact text can vary slightly between ICU versions)

en_IN: 15 October 2026
ta_IN: 15 அக்டோபர் 2026
hi_IN: 15 अक्तूबर 2026

• The pattern d MMMM y uses ICU pattern letters, which differ from PHP's date() letters (MMMM is the full month name, y the year).
• Instead of a pattern, predefined styles such as IntlDateFormatter::LONG produce the conventional format for each locale.
• The intl extension must be installed (it is included in most PHP distributions and Docker images).

Relative Formatting: "5 Minutes Ago"

Social feeds and comment sections often show relative times. A small function can produce them:

<?php
function timeAgo(DateTimeInterface $then, DateTimeInterface $now): string
{
    $seconds = $now->getTimestamp() - $then->getTimestamp();

    if ($seconds < 60) {
        return 'just now';
    }

    if ($seconds >= 7 * 86400) {
        return 'on ' . $then->format('d M Y');
    }

    foreach ([['day', 86400], ['hour', 3600], ['minute', 60]] as [$unit, $size]) {
        if ($seconds >= $size) {
            $count = intdiv($seconds, $size);
            return $count . ' ' . $unit . ($count === 1 ? '' : 's') . ' ago';
        }
    }

    return 'just now';
}

$now = new DateTimeImmutable('2026-10-15 14:05:09', new DateTimeZone('Asia/Kolkata'));

foreach (['-30 seconds', '-1 minute', '-5 minutes', '-3 hours', '-2 days', '-10 days'] as $offset) {
    echo str_pad($offset, 12) . timeAgo($now->modify($offset), $now) . "\n";
}

Output

-30 seconds just now
-1 minute   1 minute ago
-5 minutes  5 minutes ago
-3 hours    3 hours ago
-2 days     2 days ago
-10 days    on 05 Oct 2026

How It Works

1. The difference in seconds is calculated from the timestamps.
2. Anything under a minute is "just now"; anything older than a week shows the actual date, because "47 days ago" is less useful than a date.
3. The loop picks the largest fitting unit and adds an "s" for plurals.
4. $now is a parameter instead of being created inside the function, which makes the function testable with fixed dates — as in this example.

When displaying relative times, include the exact time in the HTML for accessibility and tooltips: <time datetime="2026-10-15T14:05:09+05:30" title="15 Oct 2026, 2:05 PM">5 minutes ago</time>.

Common Mistakes

Confusing m and i

Effect: H:m prints the month instead of minutes (14:10).

Fix: Minutes are i; month is m.

Confusing l and L

Effect: L prints 0/1 (leap year) instead of the weekday.

Fix: The weekday name is lowercase l.

Unescaped Letters in Text

Effect: Words inside the format are replaced by date values.

Fix: Escape literal letters with a backslash, and use single-quoted strings.

Storing Display Formats

Effect: Ambiguous dates (05/06/2026) and incorrect sorting.

Fix: Store Y-m-d / ISO 8601; format only for display.

Expecting date() to Translate

Effect: English month names on a Tamil or Hindi website.

Fix: Use IntlDateFormatter.

Best Practices

• Use DateTimeImmutable::format() with explicit time zones for all display formatting.
• Use ISO 8601 for storage and data exchange, and local formats only for display.
• Use the predefined constants (DATE_ATOM, DATE_RFC2822, DATE_RFC7231) for standard formats.
• Escape literal letters and keep format strings in single quotes.
• Use IntlDateFormatter for non-English output, and keep relative-time functions testable by passing "now" in.

Official reference: https://www.php.net/manual/en/datetime.format.php