How is seconds vs milliseconds decided?

Values with absolute value ≥ 10^12 are treated as milliseconds; everything else as seconds. This covers every real timestamp from 1970 through the year 5138 (in seconds).

Which timezone is used?

The ISO 8601 output is in UTC. The `Local` line uses your machine's timezone.

Can I use it for future dates?

Yes. Any 32- or 64-bit Unix timestamp works, including past and future values.

Unix timestamp converter

Convert between Unix timestamps and ISO 8601 dates. Auto-detects seconds vs milliseconds.

Runs in your browser Instant No signup, no tracking

Timestamp or date

Converted

About this tool

Paste a Unix timestamp (seconds or milliseconds — the tool auto-detects based on magnitude) and get the equivalent ISO 8601, RFC 2822, and local date. Or paste a date string and get the reverse. Handy for debugging JWT `exp` claims, log files, database `created_at` columns, and API timestamps. Everything runs in your browser.

Example

Paste the input on the left and you will get output like this:

Sample Timestamp or date

1704067200

Resulting Converted

Unix seconds: 1704067200
Unix milliseconds: 1704067200000
ISO 8601 (UTC): 2024-01-01T00:00:00.000Z
RFC 2822: Mon, 01 Jan 2024 00:00:00 GMT
Local: Mon Jan 01 2024 00:00:00 GMT+0000 (Coordinated Universal Time)

How to use Unix timestamp converter

Paste or type your Timestamp or date into the left pane.
The Converted appears instantly in the right pane. Conversion runs in your browser — nothing is uploaded.
Copy the result to your clipboard or download it as a file.

FAQ

How is seconds vs milliseconds decided?: Values with absolute value ≥ 10^12 are treated as milliseconds; everything else as seconds. This covers every real timestamp from 1970 through the year 5138 (in seconds).
Which timezone is used?: The ISO 8601 output is in UTC. The `Local` line uses your machine's timezone.
Can I use it for future dates?: Yes. Any 32- or 64-bit Unix timestamp works, including past and future values.