Question 1

What is an epoch timestamp?

Accepted Answer

An epoch timestamp (also called Unix time or POSIX time) is the number of seconds that have elapsed since January 1, 1970 00:00:00 UTC, excluding leap seconds. It is widely used in computing, programming, databases, and APIs to represent a specific point in time as a single integer.

Question 2

What's the difference between seconds and milliseconds?

Accepted Answer

Unix timestamps in seconds are 10 digits long (e.g. 1700000000). JavaScript and some systems use milliseconds (13 digits, e.g. 1700000000000). The tool auto-detects the format: if the value is 10 digits, it's treated as seconds; if 13 digits, as milliseconds.

Question 3

What timezones are supported?

Accepted Answer

All IANA timezone identifiers are supported, including UTC, America/New_York, Europe/London, Asia/Shanghai, Asia/Tokyo, Australia/Sydney and hundreds more. The tool uses your browser's built-in Intl API to handle daylight saving time and historical zone changes correctly.

Question 4

Can I convert a date back to an epoch timestamp?

Accepted Answer

Yes. Use the date-to-epoch panel: pick a date and time, choose a timezone, and the tool instantly shows the corresponding Unix timestamp in seconds and milliseconds.

📥 Epoch → Date

📅 Date → Epoch