HTTP Date Format Converter

Q: What is the HTTP date format?

`EEE, dd MMM yyyy HH:mm:ss GMT`, e.g. **Thu, 13 Aug 2026 14:30:00 GMT**. HTTP/1.1 (RFC 7231) requires the IMF-fixdate form; GMT is mandatory.

Q: What is the difference between HTTP date and RFC 2822?

Nearly identical, but HTTP requires **GMT** (numeric offsets are not allowed) and always includes the weekday. RFC 2822 (email) allows numeric offsets and makes the weekday optional.

Q: What cookie date format do browsers accept?

Browsers parse the **Netscape cookie spec** date: `EEE, dd-MMM-yyyy HH:mm:ss GMT` (and relaxed variants). This converter outputs the canonical form that all major browsers accept.

HTTP servers and clients exchange dates in RFC 7231 / IMF-fixdate format: `Thu, 13 Aug 2026 14:30:00 GMT`. The same family covers Netscape cookie `Expires` dates (RFC 6265) and SMTP message dates (RFC 5322). All three are "RFC 822-style" dates but differ subtly in required zone and weekday handling.

This converter renders your date-time in the HTTP header form, the cookie expiry form (also used by `Expires` in Set-Cookie), and the SMTP date form, so you can paste the right string into any header.

Timezone:

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

HTTP Date Format Converter Quick Reference

Format	Pattern / Description	Example 1	Example 2
HTTP / RFC 1123	Web Headers	Thu, 13 Aug 2026 14:30:00 GMT	Thu, 01 Jan 2026 00:00:00 GMT
Netscape Cookie	Old cookie format	Thu, 13-Aug-2026 14:30:00 GMT	Thu, 01-Jan-2026 00:00:00 GMT
SMTP Date	RFC 2822 Mail	Thu, 13 Aug 2026 14:30:00 UT	Thu, 01 Jan 2026 00:00:00 UT

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

When to Use HTTP Date Format

HTTP response debugging

Verify `Date`, `Last-Modified`, `Expires` and `If-Modified-Since` headers are correctly formatted and GMT-based when testing CDNs and caches.

Cookie expiration

`Set-Cookie: ...; Expires=Thu, 13 Aug 2026 14:30:00 GMT` must use this exact format or browsers ignore the cookie. Generate the string for cookie jars and tests.

Email & newsgroup headers

SMTP `Date:` headers use the 822 family. Generate dates for mailers, list software and news feeds.

Frequently Asked Questions

What is the HTTP date format?

`EEE, dd MMM yyyy HH:mm:ss GMT`, e.g. Thu, 13 Aug 2026 14:30:00 GMT. HTTP/1.1 (RFC 7231) requires the IMF-fixdate form; GMT is mandatory.

What is the difference between HTTP date and RFC 2822?

Nearly identical, but HTTP requires GMT (numeric offsets are not allowed) and always includes the weekday. RFC 2822 (email) allows numeric offsets and makes the weekday optional.

Why must HTTP dates be in GMT?

Specifying a single zone makes header comparison trivial — caches and validators subtract dates without timezone conversion. Sending local time in a `Date` header is a spec violation.

What cookie date format do browsers accept?

Browsers parse the Netscape cookie spec date: `EEE, dd-MMM-yyyy HH:mm:ss GMT` (and relaxed variants). This converter outputs the canonical form that all major browsers accept.

Related Time Format Converters

RFC 2822 Date Converter

Convert any date to RFC 2822 format (Sat, 13 Aug 2026 14:30:00 +0000) for email headers, HTTP headers and RSS. Free online converter with examples.

UTC Time Converter (Coordinated Universal Time)

Convert any local time to UTC (Coordinated Universal Time) instantly. See the UTC string, Z-suffixed ISO form and GMT equivalent. Free UTC converter.

RFC 3339 Date-Time Converter

Convert any date to RFC 3339 format (2026-08-13T14:30:00Z or +00:00 offset). The timestamp standard for JSON APIs and cloud services. Free converter.

All Format Guides

Unix Timestamp ISO 8601 ISO Week Date ISO Ordinal Date Military Time Decimal Time RFC 2822 RFC 3339 SQL Datetime Julian Date HTTP Date Excel Serial Date GPS Time UTC Time Cron Expression

Browse all 50 format guides →

Need to Convert Between All Formats?

Use the main Time Format Converter for instant conversion across 100+ formats — epoch, ISO 8601, RFC 3339, SQL datetime, military time and more in one click.

Open Time Format Converter