Unix Timestamp Converter

What this tool does

Unix Timestamp Converter turns epoch numbers into readable dates and dates into epoch numbers. It auto-detects seconds, milliseconds, microseconds and nanoseconds, shows ISO 8601, RFC 2822 and zone-specific times, ticks a live epoch clock and converts whole lists at once with CSV export.

Logs, databases, JWTs and APIs store time as a Unix timestamp: the number of seconds since 00:00:00 UTC on 1 January 1970, ignoring leap seconds. The number is compact and unambiguous, but 1700000000 means nothing at a glance, and it is easy to confuse seconds with the milliseconds that JavaScript, Java and many message queues use.

This converter detects the unit from the length of the number: 10 digits are seconds, 13 are milliseconds, 16 are microseconds and 19 are nanoseconds, and you can override the guess. Results are shown in UTC and in any IANA time zone using your browser’s built-in time-zone database, so daylight-saving changes are handled correctly. Large microsecond and nanosecond values are parsed with BigInt to avoid rounding, and all conversion happens on your device.

How to use Unix Timestamp Converter

1. Read the current epoch time in seconds and milliseconds at the top; use the copy buttons to grab it.
2. Choose your Time zone; the tool starts with the zone your browser reports.
3. Type or paste a number into Unix timestamp to see ISO 8601, RFC 2822, the zoned time, weekday and relative time.
4. To go the other way, pick a date and time under Date to timestamp; it is interpreted in the selected zone.
5. For many values, paste one timestamp or date per line into Batch convert and download the table as CSV.
6. If a value is detected in the wrong unit, set Timestamp unit explicitly.

Tips for better results

• JWT exp, iat and nbf claims are in seconds; JavaScript Date.now() returns milliseconds.
• Signed 32-bit timestamps overflow at 2147483647, which is 03:14:07 UTC on 19 January 2038. Store time in 64-bit fields.
• Negative timestamps are valid and represent dates before 1970, for example -86400 is 31 December 1969.
• Batch mode also accepts ISO dates such as 2024-02-29T12:00:00Z and returns their epoch seconds and milliseconds.

Common use cases

• Reading created_at and updated_at values from database exports and logs.
• Checking when a JWT or signed URL expires.
• Converting a meeting or release time in one zone into an epoch value for configuration.
• Converting a column of timestamps for a spreadsheet or incident report.

Common mistakes to avoid

• Treating milliseconds as seconds, which produces dates tens of thousands of years in the future.
• Forgetting that a date without a zone is ambiguous; always check which zone the Date to timestamp field uses.
• Assuming Unix time counts leap seconds. It does not, so every day is exactly 86,400 seconds.