Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates. All calculations happen locally.
About Unix Timestamps
A Unix timestamp is the number of seconds elapsed since 1 January 1970 00:00:00 UTC (the Unix Epoch). It is timezone-independent and used universally in computing, databases, and APIs. See: MDN Date reference. Read more: Timestamp Conversion Methods Across Programming Languages.
JavaScript's Date.now() returns milliseconds — divide by 1000 to get seconds.
Common Use Cases
- Database timestamps — storing event times
- JWT expiry —
expis a Unix timestamp. Decode it with the JWT Debugger. - Log files — precise event ordering
- Cache control — expiration times
- Scheduling — future event planning
Key Facts
- Always in UTC — convert to local time for display
- 32-bit max is
2147483647(Jan 2038) - JavaScript uses milliseconds internally
- Negative values represent dates before 1970
- Leap seconds are not counted
Frequently Asked Questions
Seconds vs milliseconds?
Unix timestamps are conventionally in seconds. JavaScript's Date.now() returns milliseconds. Divide by 1000 to get seconds; multiply by 1000 to feed into new Date().
What is the Y2K38 problem?
32-bit signed integers overflow on 19 January 2038. Modern systems use 64-bit integers and won't have this issue.
Are timestamps timezone-aware?
No. A Unix timestamp always represents a moment in UTC. Timezone conversion is done at display time.
Why are some APIs in milliseconds?
JavaScript popularised millisecond precision. Always check the API docs — look at the number of digits: 10 digits = seconds, 13 digits = milliseconds.