Timestamp Converter

A log file or API gave you a number instead of a date

Server logs, CDN exports, analytics tables and APIs can record time as an epoch value such as 1704067200. That is precise but unreadable. This page turns it into a date you can reason about, and turns a date back into epoch seconds when a tool or query asks for one. Results appear in a small table with a UTC ISO 8601 value, an HTTP-style GMT string and your local time. No request is made to any server.

Step by step

1. Enter a value in seconds, milliseconds or microseconds in the Unix Timestamp box, then press Timestamp → Date. The date picker updates and the table appears.
2. Going the other way, choose a moment in the Human Readable picker and press Date → Timestamp. The number box fills with the result.
3. Press Set Current Time to load the present moment into both boxes.
4. Take the value you need from the table rows: Unix Timestamp, ISO 8601, RFC 2822 or Local.

What to watch for

Units are the classic trap, and the converter guesses them by counting digits. A 13 digit number is handled as milliseconds (what JavaScript's Date.now() returns), and a 16 digit one as microseconds, which Google Analytics 4 uses for event_timestamp in its BigQuery export. Both are scaled to seconds before converting. Any other length is taken as seconds, which misreads nanoseconds (19 digits) and pre 2001 millisecond values (12 digits), so divide those by hand.

The picker has no time zone setting. It uses the zone your operating system reports and has minute precision, so a date you pick converts to a timestamp ending in :00 seconds, and a colleague in another zone who picks the same clock time gets a different number. The ISO 8601 row is always shown in UTC, which is the safest format to paste into a sitemap or into datePublished and dateModified in schema.

The row labeled RFC 2822 is the browser's UTC string, ending in GMT, which is the same shape as the Last-Modified and Date headers your server sends.

Questions people ask

What is a Unix timestamp?

A count of seconds since midnight UTC on January 1, 1970. It ignores time zones, which makes it handy for comparing events across systems.

Can I enter a date before 1970?

Yes. Earlier dates produce negative timestamps, and negative numbers convert back correctly.

Why is my converted date off by a few hours?

You are probably comparing UTC with local time. Check the Local row against the ISO 8601 row; the gap is your time zone offset.

Further reading: XML Sitemap Strategy Beyond One Big File: Index Sitemaps, Segmentation, and Using lastmod to Steer Crawling and Log File Analysis for SEO: The Complete Guide.

The same tool is also published on the static mirror at seoprocheck.github.io, and the rest of the set is on the free tools page.