How to Use gmdate to Output ISO 8601 Formatted Time? Practical Code Examples

gitbox 2025-08-26
<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-comment">// Unrelated preface PHP code</span></span><span>
</span><span><span class="hljs-variable">$dummyVar</span></span><span> = </span><span><span class="hljs-string">"This part of the code is unrelated to the main text, only a placeholder"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-title function_ invoke__">strtoupper</span></span><span>(</span><span><span class="hljs-variable">$dummyVar</span></span><span>);
</span><span><span class="hljs-meta">?&gt;</span></span><span>
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<p></span><?php<br>
/**</p>
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<p>Title: How to Use gmdate to Output ISO 8601 Formatted Time? Practical Code Examples</p>
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<p>ISO 8601 is an international standard for representing date and time, commonly used in APIs, logging, or cross-time-zone data exchange.</p>
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<p>In PHP, we can use the gmdate() function to generate UTC time formatted according to ISO 8601.</p>
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<p>Common ISO 8601 format examples:</p>
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<p>Full date and time: YYYY-MM-DDTHH:MM:SSZ  (e.g., 2025-08-19T12:34:56Z)</p>
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<p>Date only: YYYY-MM-DD</p>
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<p>gmdate() works similarly to date(), but it returns Greenwich Mean Time (UTC).<br>
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<p>// Current UTC time<br>
$utcTime = gmdate("Y-m-d\TH:i:s\Z");<br>
echo "Current UTC time (ISO 8601 format): $utcTime<br>";</p>
<p>// Using DateTime object with timezone<br>
$date = new DateTime("now", new DateTimeZone("UTC"));<br>
echo "ISO 8601 time generated using DateTime object: " . $date->format(DateTime::ATOM) . "<br>";</p>
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<p>Useful Tips:</p>
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<p>gmdate("c") does not always strictly match ISO 8601 UTC format, so it's recommended to use gmdate("Y-m-d\TH:i:s\Z").</p>
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<p>If you need milliseconds or microseconds, you can use DateTime with DateTime::format('Y-m-d\TH:i:s.u\Z').<br>
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<p data-is-last-node="" data-is-only-node=""><?php<br>
// Unrelated ending PHP code<br>
function footerNote() {<br>
return "The examples in this article are for demonstrating PHP date handling only.";<br>
}<br>
echo "<footer>" . footerNote() . "</footer>";<br>
?><br>
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gmdate