Convert Unix epoch to ISO date and back
Paste seconds or milliseconds, get ISO 8601 and local time, or pick a date and copy the epoch.
Paste a timestamp to get ISO, local time, and UTC. The tool auto-detects seconds vs milliseconds.
Enter a date or ISO string to get seconds and milliseconds. Handy for logs, JWT exp, and SQL TIMESTAMP values.
1700000000 is 2023-11-14T22:13:20.000Z. Thirteen digits, such as 1700000000000, are milliseconds and land about 30 years later if you treat them as seconds. JWT exp and iat are seconds. JavaScript Date.now() is milliseconds. SQL TIMESTAMP WITHOUT TIME ZONE does not store the offset, so convert to UTC before you copy the number into a log. An ISO string with +03:00 and one with Z can be the same instant. This page is the converter with both directions open, not a glossary entry about the epoch.
FAQ
Seconds or ms?
About 10 digits usually means seconds, 13 means milliseconds. You can switch manually.
Which ISO format?
Standard ISO 8601 with Z or an offset, depending on the mode.
Are offsets supported?
Yes. Strings with +03:00 and Z are handled correctly.