RFC 2822 Date

RFC 2822 date formatting is the email and HTTP-era way to write an instant as a weekday, day, month, year, time, and timezone offset (or GMT). This converter formats a calendar date into an RFC 2822 / HTTP-date string and parses pasted strings back into ISO 8601 and Unix seconds. It sits beside the ISO 8601 converter when you need legacy email headers, HTTP Date headers, or older APIs that still speak RFC 1123 style GMT dates.

RFC 2822 vs ISO 8601

ISO 8601 prefers machine-sorted forms like 2024-01-15T12:00:00Z. RFC 2822 prefers human-readable English month names: Mon, 15 Jan 2024 12:00:00 GMT. HTTP Date (RFC 7231) uses a strict subset with GMT. Browsers’ toUTCString() output matches that HTTP-date shape, which is what this tool surfaces as the primary RFC 2822 (UTC) line.

Use ISO when exchanging data between modern APIs. Use RFC 2822 when writing email Date headers, debugging CDN Age/Date headers, or talking to libraries that still parse Date: lines from RFC 5322 messages (the successor numbering to 2822).

How to use the fields

Paste an RFC-style string into Value, or pick a calendar date to format noon UTC for that day. The result lists the UTC RFC string, ISO 8601, Unix seconds, and the browser’s local string for sanity checks. Invalid paste input returns a clear parse error instead of a silently wrong epoch.

Worked example

Picking 15 January 2026 formats a GMT HTTP-date for noon UTC that day. Pasting that string back should recover the same Unix seconds. Comparing ISO and RFC lines side by side helps when a log shows one format and a ticket shows the other.

Parsing pitfalls

Locale-specific month names outside English, missing commas, or numeric timezones without a matching offset can fail browser Date parsing. Prefer GMT/UTC forms for interoperability. Unix milliseconds pasted without conversion may look like far-future dates — Discord-style seconds are handled on Discord timestamp, and raw epoch work belongs on Unix timestamp.

Related converters

See the converters hub for Excel serials, FILETIME, LDAP timestamps, and calendar systems. For historical Julian civil dates rather than string formats, open Julian ↔ Gregorian.

Email, HTTP, and logging

Mail servers emit Date headers in RFC 5322 form. CDNs and origin servers emit Date and Last-Modified in HTTP-date GMT. When correlating a support ticket timestamp with a log line, converting both to Unix seconds on this page (or the Unix tool) removes format ambiguity. Keep times in UTC when writing public APIs even if you display RFC locally.

Security and spoofing caveats

Never trust a Date header alone for security decisions — clocks lie and clients spoof. Use this converter for readability and debugging only. Signed tokens and replay windows should rely on server-side trusted time, not pasted header strings.

For Windows FILETIME integers from Active Directory, use FILETIME converter or LDAP timestamp instead of RFC parsing.

Common string shapes you will see

Examples include Mon, 15 Jan 2024 12:00:00 GMT and variants with numeric offsets like -0500. Prefer GMT/UTC when writing interoperable headers. Some libraries accept RFC 5322 obsolete forms; if the browser cannot parse a rare variant, normalize to GMT first.

When a CDN log shows age based on Date and a browser shows local time, convert both to Unix seconds on this page to compare apples to apples. Mixing RFC display strings without converting to an absolute instant is a frequent source of “off by a few hours” bug reports.

Programming and QA workflows

QA engineers paste failing Date headers into this converter while reproducing API bugs. Developers compare the RFC line to ISO in failing fixtures. Because everything runs client-side, no customer PII leaves the browser when you paste production header samples into the field — still redact tokens and cookies from any shared screenshots.

For Excel serial dates coming from spreadsheets rather than HTTP, use Excel date converter. For Windows 100-nanosecond intervals, use FILETIME tools instead.

Historical note

RFC 2822 updated earlier email date practice; RFC 5322 supersedes it for Internet Message Format. HTTP Date remains specified with GMT. Day-to-day, “RFC 2822 date” still names the familiar English-month GMT string. This page targets that practical need rather than implementing every obsolete grammar production in the RFCs.

Copy/paste hygiene

Avoid rich-text paste that inserts invisible Unicode spaces into Date headers. Prefer plain text. Strip surrounding quotes. If a string includes a display name or angle-bracket email address from a From line, paste only the date-time portion. After a successful parse, compare Unix seconds with a second tool such as Unix timestamp to confirm agreement before filing a bug.

When documenting an incident timeline, standardize on ISO 8601 in the write-up and keep RFC strings only when quoting raw headers. Readers scanning a postmortem should not have to mentally parse weekday abbreviations.

Bookmark this converter next to your ISO and Unix tools so format translation never blocks a debugging session. Small utilities like this keep date bugs boring — and boring date bugs are the ones that get fixed quickly.