Unix time guide
Convert Unix time in seconds or milliseconds, plus common 16-digit microseconds and 19-digit nanoseconds, to a readable date, or turn an ISO 8601 date into a Unix timestamp. VetaTool keeps the original high-precision value visible while showing the millisecond-precision date locally in your browser. This tool is free to use. No account or payment is required.
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Unix timestamps count elapsed time from 1970-01-01T00:00:00Z. Ten-digit values commonly represent seconds, while thirteen-digit values commonly represent milliseconds.
The converter recognizes common 16-digit microsecond and 19-digit nanosecond inputs before applying the existing seconds-versus-milliseconds magnitude heuristic. JavaScript dates have millisecond precision, so sub-millisecond digits are preserved in the original-value detail while the readable date is truncated to milliseconds.
ISO 8601 values ending in Z use UTC, while values with an offset such as +09:00 preserve that offset during parsing. Calendar inputs without an offset are interpreted as UTC rather than silently using the browser timezone.
Add multiple rows when you need to inspect log events, API expiry times, database values, or dates from different systems. Each row can use its own conversion direction and can be copied independently.
The Unix value 1700000000 represents seconds and converts to a stable UTC ISO date.
1700000000ISO: 2023-11-14T22:13:20.000Z
Seconds: 1700000000
Milliseconds: 1700000000000Common questions
Common 16-digit integers are interpreted as microseconds and 19-digit integers as nanoseconds. Other numeric values keep the existing rule: absolute values of at least 100,000,000,000 are milliseconds and smaller values are seconds.
Supported calendar and date-time inputs without an explicit offset are interpreted as UTC.
Yes. Negative Unix timestamps are accepted when they produce a valid JavaScript date.
No. Date parsing and timestamp conversion run locally in your browser.
Looking for broader references? Browse all developer guides.
Debugging a specific Timestamp issue? Browse Timestamp troubleshooting.