04 / Forge / Developer / Client-side
Timestamp converter
Unix seconds or milliseconds to ISO 8601 and local time, and back. Runs entirely in your browser; nothing you enter leaves the page.
What this timestamp converter does
Paste a Unix timestamp and the tool shows it as an ISO 8601 string in UTC and as local time in your browser's timezone. Paste a date instead and it returns the epoch value in seconds and milliseconds. Ten-digit values are treated as seconds and thirteen-digit values as milliseconds, which covers every timestamp you will meet in logs, databases, and APIs.
Why the unit matters
A common bug is treating milliseconds as seconds, which produces dates around the year 50000, or the reverse, which produces January 1970. The tool shows both interpretations so the mistake is visible immediately.
Questions
What is a Unix timestamp?
The number of seconds since 1 January 1970 00:00:00 UTC. Many systems store it in milliseconds instead, which is the same count multiplied by one thousand.
Which timezone is used for local time?
The timezone your browser reports. The UTC value is shown alongside so there is no ambiguity.
Can I convert a date to a timestamp?
Yes. Enter an ISO 8601 date or anything your browser can parse and the tool returns seconds and milliseconds.
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