Convert between Unix epoch timestamps and human-readable dates. Live counter, seconds and milliseconds both supported.
A Unix timestamp counts the seconds elapsed since 1 January 1970 00:00:00 UTC, independent of timezone. It is the standard time representation in operating systems, programming languages, APIs, and log files. This tool converts any epoch value to UTC, your local timezone, and ISO 8601 format, and reverses the process for any date you enter.
Timestamps of 13 or more digits are automatically treated as milliseconds - the default format in JavaScript's Date.now(). The Y2K38 problem describes the 32-bit signed integer overflow that will occur on 19 January 2038 at 03:14:07 UTC; 64-bit systems running modern software are not affected.
Common operations: to get the current Unix timestamp in a terminal run date +%s on Linux/macOS or [int][DateTimeOffset]::UtcNow.ToUnixTimeSeconds() in PowerShell. In Python use int(time.time()); in JavaScript use Math.floor(Date.now() / 1000).
When reading timestamps from logs or API responses, always confirm whether the value is in seconds or milliseconds - a 10-digit number is seconds (standard Unix), a 13-digit number is milliseconds (JavaScript default). Mixing them up causes dates to appear 1000x in the future or past, a common source of off-by-three-orders-of-magnitude bugs.