Unix Timestamp Converter
Convert between Unix timestamp (seconds since epoch) and human-readable date.
Formula
Date ↔ Unix seconds since 1970
How to use
- 1Enter a Unix timestamp (10 digits for seconds).
- 2Read the ISO (UTC) and local date formats.
- 3Use the milliseconds value for systems that need finer resolution.
About this calculator
Computers store time as a single number: the count of seconds since the start of 1970. That is a Unix timestamp - perfect for machines, meaningless at a glance. This converter turns one into a human-readable date in both UTC and your local time, so you can tell exactly when something happened.
Formula explained
A Unix timestamp counts seconds since midnight UTC on 1 January 1970 (the epoch). Many environments, JavaScript included, use milliseconds, so the conversion multiplies seconds by 1000 before formatting. The result is shown as an ISO 8601 UTC string and as a local date adjusted to your timezone.
Worked example
1735689600 → 1 January 2025, 00:00:00 UTC (1,735,689,600,000 ms). Your local display depends on your timezone offset, though the underlying instant is identical everywhere.
Tips & notes
- Check the digit count to tell seconds (10) from milliseconds (13) before converting.
- Convert everything to UTC when comparing events to avoid timezone confusion.
- Store times as epoch values where you can, since they compare and sort cleanly.