Unix Timestamp Converter
Convert Unix epoch timestamps to human-readable dates in multiple formats, or convert date strings to Unix timestamps. Supports seconds and milliseconds.
How the Unix Timestamp Converter Works
A Unix timestamp (also called epoch time or POSIX time) represents the number of seconds that have elapsed since January 1, 1970, at 00:00:00 UTC, known as the Unix epoch. This tool converts between Unix timestamps and human-readable date formats in both directions.
Conversion Formula
Timestamp to Date: The timestamp (in seconds) is multiplied by 1000 to get milliseconds, then passed to the JavaScript Date constructor. The tool auto-detects whether your input is in seconds or milliseconds based on the magnitude of the number.
Date to Timestamp: The date string is parsed using the Date constructor, and the resulting millisecond value is divided by 1000 to produce the Unix timestamp in seconds.
Why Developers Use Unix Timestamps
Unix timestamps are the universal language for representing time in software systems. They are timezone-independent, making them ideal for distributed systems where servers, databases, and clients operate in different time zones. A timestamp of 1700000000 means the same moment in time regardless of whether you are in New York, London, or Tokyo.
Databases store timestamps as integers because they are compact (just a number) and can be compared, sorted, and indexed efficiently. APIs return timestamps because they eliminate ambiguity about date formats and time zones. Log files use timestamps for precise, sortable time ordering of events.
Seconds vs. Milliseconds
The traditional Unix timestamp is measured in seconds. However, JavaScript and many modern APIs use milliseconds since the epoch. This tool automatically detects which format you are using. If your number has 10 digits, it is treated as seconds. If it has 13 digits, it is treated as milliseconds. You can also manually specify the unit.
Output Formats
When converting a timestamp to a date, this tool shows multiple formats simultaneously: ISO 8601 format for standards compliance, your local time zone representation for everyday readability, UTC format for server-side contexts, and a relative time description (for example, "3 hours ago" or "in 2 days") for quick context.
Common Timestamps to Know
The Unix epoch itself (timestamp 0) is January 1, 1970. The Y2K38 problem refers to January 19, 2038, when the 32-bit signed integer used for timestamps in older systems will overflow. The current Unix timestamp at any moment can be obtained in most programming languages with a single function call.
Use Cases for Timestamp Conversion
Developers frequently convert timestamps when debugging API responses, reading database records, analyzing server logs, configuring cache expiration times, setting JWT expiration claims, or interpreting analytics data. This tool makes those conversions instant and eliminates the mental math of counting seconds from 1970.
Privacy Notice
All conversions happen entirely in your browser. No data is transmitted to any server.