Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and back. Supports seconds and milliseconds, UTC and local time. All in your browser.
Runs in your browser — nothing uploaded
Now
Unix (seconds)
Unix (ms)
ISO 8601 (UTC)
Timestamp → Date
Type a number to convert.
Date → Timestamp
Type a date in almost any common format.
Use this free Unix timestamp converter to translate between epoch time and human dates. It supports seconds and milliseconds, shows local time alongside UTC and ISO 8601, and includes a live "current time" reference plus relative ("3 hours ago") framing.
Private by design — your data never leaves your device
How to use it
No account, no upload — it all happens on your device.
1
Click Use current time to drop the current epoch into the timestamp box.
2
Pick Seconds or Milliseconds depending on the format your data uses.
3
Edit the timestamp to see the equivalent local time, UTC, ISO 8601, and a human-friendly relative description.
4
Or paste a date in any reasonable format into the right box to get its timestamp.
Same moment, different formats
A worked round-trip so you can spot which one your data is using.
| Format | Example for 2024-06-01 12:00:00 UTC |
|---|---|
| Unix seconds | 1717243200 |
| Unix milliseconds | 1717243200000 |
| ISO 8601 (UTC) | 2024-06-01T12:00:00.000Z |
| ISO 8601 (offset) | 2024-06-01T08:00:00-04:00 (US Eastern, DST) |
| RFC 2822 | Sat, 01 Jun 2024 12:00:00 GMT |
| Local (New York) | 2024-06-01 08:00:00 |
| Local (London) | 2024-06-01 13:00:00 (BST) |
| Local (Tokyo) | 2024-06-01 21:00:00 |
Spotting seconds vs milliseconds at a glance
If your timestamp lands in the wrong decade, you got the unit wrong.
- 10 digits ≈ seconds.
1717243200→ June 2024. - 13 digits ≈ milliseconds.
1717243200000→ June 2024. - 16+ digits ≈ microseconds (rare — Postgres
timestamptzinternally, some tracing systems). - 19 digits ≈ nanoseconds (Go, gRPC traces).
When in doubt, divide by 1000 once and see if the date jumps from year 56,000 back into a reasonable range.
Storing time well
- Database: use a timestamp-with-timezone column (Postgres
timestamptz, MySQLTIMESTAMP). Store everything as UTC. Convert for display in the application layer. - API: serialise as ISO 8601 with a
Zsuffix or explicit offset. Avoid plain Unix seconds in user-facing APIs — they're ambiguous between seconds and milliseconds. - Frontend display:respect the user's locale and timezone via
Intl.DateTimeFormat. Pre-formatting on the server defeats this. - Logs: RFC 3339 (basically ISO 8601 with stricter rules) — sortable as a string, unambiguous, plays well with grep.
Frequently asked
What is a Unix timestamp?
A Unix timestamp is the number of seconds elapsed since 1 January 1970 UTC (the Unix epoch). It is the most common way databases and APIs store points in time because it is timezone-independent and easy to compare arithmetically.
Seconds or milliseconds — which one is mine?
Rule of thumb: 10-digit numbers are seconds, 13-digit numbers are milliseconds. JavaScript and many APIs use milliseconds; Unix tooling, MySQL, and Postgres typically use seconds. Toggle the unit dropdown if the converted date is wildly off.
Why is my local time different from UTC?
Local time depends on your operating system's timezone setting and current daylight-saving rules. UTC is a fixed reference that never shifts. When storing timestamps in a database or sending them between services, prefer UTC or an ISO 8601 string with an explicit offset.