Unix Timestamp Converter — Free Online
Convert Unix epoch timestamps to human-readable dates and back. Supports seconds and milliseconds, with timezone selection and DST-accurate conversion using the IANA timezone database.
How to Use the Unix Timestamp Converter
- Choose direction: "Timestamp → Human Date" to decode a Unix timestamp, or "Date → Timestamp" to encode a date
- For timestamp-to-date: enter any Unix timestamp in seconds (10 digits) or milliseconds (13 digits)
- Click "Now" to instantly fill in the current Unix timestamp
- For date-to-timestamp: select your date and time using the datetime picker
- Click "Convert" to see the result — copy it with the copy button
How the Unix Timestamp Converter Works — The Formula
A Unix timestamp counts the number of seconds (or milliseconds) elapsed since the Unix Epoch — January 1, 1970, 00:00:00 UTC. This is timezone-independent and monotonically increasing, making it ideal for computer systems.
Unix Timestamp (seconds) = (Date − 1970-01-01T00:00:00Z) in seconds
To Human Date:
datetime = epoch + timestamp_seconds
apply target timezone offset
Milliseconds = Unix Timestamp × 1000
Detection: 10-digit = seconds, 13-digit = milliseconds
Formula validated by Vipul Jaganiya, Computer Science expert in Calendar Mathematics and Timezone Engineering. Correctly handles negative timestamps (pre-1970 dates) and the Y2K38 boundary.
Real-World Examples
| Unix Timestamp | Human Date (UTC) | Note |
|---|---|---|
| 0 | 1970-01-01 00:00:00 | Unix Epoch origin |
| 1000000000 | 2001-09-09 01:46:40 | One billion seconds milestone |
| 1748217600 | 2025-05-26 00:00:00 | May 26, 2025 |
| 2147483647 | 2038-01-19 03:14:07 | Y2K38 overflow boundary (32-bit) |