Unix Timestamp Converter Online
Convert Unix timestamps (epoch time) to human-readable dates and back instantly. This free online tool supports both seconds and milliseconds with automatic detection, timezone-aware conversion using all IANA timezones, and a live clock showing the current Unix timestamp. All processing happens in your browser — no data is sent to any server.
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 widely used in programming, databases, APIs, and server logs as a compact, timezone-independent way to represent a point in time. Timestamps in milliseconds (13 digits) are common in JavaScript, Java, and many web APIs.
Frequently Asked Questions
How do I convert a Unix timestamp to a date?
Paste your Unix timestamp (in seconds or milliseconds) into the input field. The tool automatically detects the format and shows the converted date with day of week, relative time, and multiple output formats including ISO 8601 and RFC 2822.
What is the difference between seconds and milliseconds?
Unix timestamps in seconds are 10 digits long (e.g., 1700000000), while millisecond timestamps are 13 digits (e.g., 1700000000000). Languages like JavaScript use milliseconds (Date.now()), while most Unix systems and languages like Python use seconds. This tool auto-detects which format you enter.
How do timezones affect timestamp conversion?
Unix timestamps are always in UTC. When converting to a human-readable date, the timezone determines how the date and time are displayed. For example, the same timestamp shows different clock times in New York (EST/EDT) and Tokyo (JST). Use the timezone selector to see the date in any timezone.
Is my data private?
Yes. All conversions happen entirely in your browser using JavaScript's built-in Date and Intl APIs. No timestamps or dates are sent to any server. Your last input and timezone preference are saved in your browser's localStorage for convenience.