Unix Timestamp Converter

A Unix timestamp converter translates between Unix timestamps (numbers representing seconds since January 1, 1970 UTC) and human-readable dates. Developers, system administrators, and data analysts use these converters daily when working with APIs, databases, log files, and server configurations.

This tool handles both seconds and milliseconds timestamps, supports ISO 8601 date strings, shows the current Unix time as a live clock, and converts to multiple date formats simultaneously.

The Unix Epoch — January 1, 1970, 00:00:00 UTC — was chosen as the reference point for Unix time when the Unix operating system was being developed at Bell Labs in the early 1970s. It was a recent, round date at the time that kept timestamp values reasonably small.

Every Unix timestamp is simply a count of seconds from this reference point. Timestamps before the Epoch are negative (e.g., -86400 represents December 31, 1969). This simple system makes time calculations trivial — the difference between two timestamps is the duration in seconds between them.

Enter a Unix timestamp (seconds or milliseconds) in the left field to see it converted to human-readable dates. Or enter a date string (ISO 8601 format like '2024-01-15T12:00:00Z') in the right field to get the Unix timestamp. Click 'Use Now' to populate both fields with the current time.

The converter shows the date in multiple formats: UTC, your local timezone, ISO 8601, and both seconds and milliseconds timestamps. Click any row to copy that value to your clipboard.

Databases typically store timestamps as integers (Unix time) or datetime types. When designing APIs, the convention is to use Unix timestamps in seconds for simplicity and interoperability. ISO 8601 strings (like '2024-01-15T12:00:00Z') are preferred when human readability is important.

For JavaScript development, Date objects internally use millisecond timestamps. The Date constructor accepts milliseconds: new Date(1700000000000). For seconds timestamps, multiply by 1000 first. When comparing dates, compare the timestamps directly rather than parsing date strings — it's faster and avoids timezone-related bugs.