About Unix Timestamp Converter

Converts between Unix (epoch) timestamps and human-readable dates in both directions. Supports seconds and milliseconds, and outputs ISO 8601, local datetime, UTC datetime, and relative time for any given timestamp. All conversions run client-side using the native JavaScript Date API.

• Timestamp to date: enter any Unix timestamp in seconds or milliseconds and get ISO 8601, local, UTC, and relative time outputs
• Date to timestamp: pick any datetime and get both the seconds and milliseconds epoch values instantly
• Use current time buttons pre-fill inputs with the current timestamp or local datetime
• Relative time output uses Intl.RelativeTimeFormat to show human-friendly strings like "3 years ago" or "in 5 minutes"
• Handles negative timestamps (pre-1970 dates) and large future timestamps without precision issues
• Copy buttons on every output field for fast workflow integration

Frequently Asked Questions

What is a Unix timestamp?

A Unix timestamp (also called epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC. It is a widely-used way to represent a specific point in time in software, databases, and APIs.

Should I use seconds or milliseconds?

Most Unix timestamps are in seconds. JavaScript's Date.now() returns milliseconds, as do many browser APIs and some databases. If your timestamp is 13 digits or longer it is almost certainly milliseconds; 10 digits means seconds. Toggle the unit in the converter to match.

Can I convert dates before 1970?

Yes. Negative timestamps represent dates before the Unix epoch (January 1, 1970). For example, -86400 is December 31, 1969, 00:00:00 UTC.

What is ISO 8601?

ISO 8601 is an international standard for representing dates and times, e.g. "2024-03-15T14:30:00.000Z". The trailing Z denotes UTC. This format is unambiguous, sortable as a string, and accepted by virtually all programming languages and databases.