What a Unix timestamp represents
A Unix timestamp counts time from 00:00:00 UTC on 1 January 1970. Ten-digit values usually represent seconds, while modern 13-digit values commonly represent milliseconds.
UTC and local time
The number itself does not contain a time zone. This tool displays both the standardized UTC representation and the local time configured in your browser.
Common debugging mistake
If a date appears thousands of years away, seconds were probably interpreted as milliseconds or vice versa. The converter detects the unit from the value's size.