PHP Date Format Converter (date() Constants)

Q: What does PHP DATE_COOKIE output?

`DATE_COOKIE` = `l, d-M-Y H:i:s T`, e.g. **Thursday, 13-Aug-2026 14:30:00 UTC** — the format Netscape cookies use.

Q: What timezone does date() use?

`date()` uses the **default timezone** set via `date_default_timezone_set()` or `ini("date.timezone")`. For UTC output, call `gmdate()` instead.

PHP's `date()` function accepts format constants like DATE_COOKIE (`Thursday, 13-Aug-2026 14:30:00 UTC`), DATE_RFC850 (`Thursday, 13-Aug-26 14:30:00 UTC`) and DATE_RFC1036 (`Thu, 13 Aug 26 14:30:00 +0000`) for cookies, legacy feeds and mail headers.

This converter renders your date-time in each PHP constant form so you can predict `date(DATE_COOKIE)` output when setting cookies or generating headers.

Timezone:

Enter a date-time above to see the conversion results.

PHP Date Format Converter (date() Constants) Quick Reference

Format	Pattern / Description	Example 1	Example 2
PHP DATE_COOKIE	Cookie format	Thu, 13-Aug-2026 14:30:00 GMT	Thu, 01-Jan-2026 00:00:00 GMT
PHP RFC 850	EEEE, dd-MMM-yy HH:mm:ss XX	Thursday, 13-Aug-26 14:30:00 GMT	Thursday, 01-Jan-26 00:00:00 GMT
PHP RFC 1036	EEE, dd MMM yy HH:mm:ss XX	Thu, 13 Aug 26 14:30:00 +0000	Thu, 01 Jan 26 00:00:00 +0000

* Examples are rendered in UTC for the fixed sample instants above.

When to Use PHP Date Format (date() Constants)

Cookie generation in PHP

`setcookie` with `date(DATE_COOKIE)` — preview the exact expiry string browsers will parse.

Legacy feed compatibility

Old RSS/Atom parsers expect RFC 850/1036 dates. Generate the legacy forms for maximum compatibility.

Mail header formatting

PHP mail headers historically used RFC 1036. Verify header strings before sending.

Frequently Asked Questions

What does PHP DATE_COOKIE output?

`DATE_COOKIE` = `l, d-M-Y H:i:s T`, e.g. Thursday, 13-Aug-2026 14:30:00 UTC — the format Netscape cookies use.

What is the difference between DATE_RFC850 and DATE_RFC1036?

`DATE_RFC850` = `l, d-M-y H:i:s T` (full weekday, 2-digit year, zone name); `DATE_RFC1036` = `D, d M y H:i:s O` (abbreviated weekday, numeric offset).

What is the PHP date format for ISO 8601?

`DATE_ISO8601` = `Y-m-dTH:i:sO` (e.g. `2026-08-13T14:30:00+00:00`). Note `c` (ISO 8601) differs slightly — it includes the offset as `+00:00` rather than `+0000` in some PHP versions.

What timezone does date() use?

`date()` uses the default timezone set via `date_default_timezone_set()` or `ini("date.timezone")`. For UTC output, call `gmdate()` instead.

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