Timestamp Converter
Convert Unix timestamps in seconds or milliseconds to human-readable date, UTC, ISO 8601, and local time online. 100% client-side browser conversion.
| Feature | Unix Seconds (10 Digits) | Unix Milliseconds (13 Digits) |
|---|---|---|
| Digit Length | 10 digits (e.g. 1700000000) | 13 digits (e.g. 1700000000000) |
| Standard Usage | Linux, POSIX, Python, PHP, MySQL, Go | JavaScript (`Date.now()`), Java, MongoDB, Node.js |
| Precision Level | 1-second precision | 1-millisecond sub-second precision |
Unix time is a system for describing a point in time defined as the number of seconds (or milliseconds) that have elapsed since the Unix Epoch (00:00:00 UTC on January 1, 1970). Unix timestamps do not embed timezone offsets. Timezone rendering is performed in your local browser using native Intl.DateTimeFormat capabilities.
What Is a Unix Timestamp?
A Unix timestamp counts the seconds (or milliseconds) elapsed since January 1, 1970 00:00:00 UTC — a compact, timezone-independent way to store a point in time that's easy for software to compare and sort.
How to Use the Timestamp Converter
- Paste a Unix timestamp to convert it to a human-readable date, or enter a date to convert it to a timestamp.
- The tool auto-detects whether a numeric value is in seconds or milliseconds based on its length — override this if needed.
- Review the result in UTC, ISO 8601, and local time.
- Use "current timestamp" to see right now in every supported format.
Technical Notes
- Timestamps in seconds have 10 digits for current dates; timestamps in milliseconds have 13 — this length difference is how automatic detection works.
- ISO 8601 (e.g. 2026-01-15T09:30:00.000Z) is an unambiguous, timezone-explicit text format widely used in APIs and logs, in contrast to a raw timestamp number.
Example
Frequently Asked Questions
How does automatic unit detection work?+
Timestamps with 10 or 11 digits are automatically parsed as seconds, whereas timestamps with 12 or 13 digits are parsed as milliseconds. You can also explicitly lock the unit preference.
Does this tool send my timestamps to an external server?+
No. All calculations are executed 100% locally in your browser using native JavaScript primitives.