Unix Timestamp Converter

Turn an epoch number into a date

Enter a timestamp, select its unit or let the page detect common second and millisecond magnitudes, then choose Convert timestamp. Results show ISO UTC, browser-local time, seconds, and milliseconds.

What Unix time measures

Unix time counts elapsed seconds from 1970-01-01 00:00:00 UTC, normally without representing leap seconds as additional numbered instants. Many browser and JavaScript APIs use milliseconds instead. The numeric value has no time-zone label because it identifies an instant; zones affect only how that instant is displayed.

Worked example

The timestamp 0 seconds becomes 1970-01-01T00:00:00.000Z. The value 1704067200 seconds becomes midnight UTC on January 1, 2024. Entering 1704067200000 as milliseconds identifies the same instant. Selecting the wrong unit creates a dramatically different date or one outside the supported range.

Automatic unit detection

Detect mode treats magnitudes of at least 100 billion as milliseconds and smaller values as seconds. That works for ordinary contemporary timestamps but cannot infer intent perfectly for far-future, historical, truncated, or unusually scaled data. Choose the unit explicitly when a database, API, or log format documents it.

UTC and local display

The UTC result uses ISO 8601 with a trailing Z. Local output uses this browser's locale and configured time zone, including applicable daylight-saving rules. Two users may see different local clock readings for the same timestamp while agreeing on the UTC instant.

Privacy and limitations

Conversion uses the browser clock and date implementation without an external request. It does not consult an authoritative time server, IANA database update service, GPS source, or business calendar. Browser date range and numeric precision apply. Historical civil-time rules can be complex, and this tool should not replace domain-specific archival or legal timekeeping systems.

Unix Timestamp FAQ

Are seconds and milliseconds interchangeable?

No. Milliseconds contain three more decimal places for the same instant.

Why does local time differ on another device?

Each browser formats the instant using its own configured locale and time zone.

Does current time contact a server?

No. It reads the clock exposed by the current device.