Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Supports seconds and milliseconds. Works offline in your browser.
Quick Actions
Unix Timestamp Tips
- Unix timestamps count seconds (or milliseconds) since January 1, 1970 UTC
- 10-digit numbers are seconds, 13-digit numbers are milliseconds
- Unix timestamps are timezone-independent (always UTC)
- Commonly used in APIs, databases, and log files
- Perfect for sorting and comparing dates programmatically
- Year 2038 problem: 32-bit systems may overflow (use 64-bit)
What is a Unix Timestamp?
A Unix timestamp (also called Epoch time or POSIX time) is a system for describing instants in time. It represents the number of seconds (or milliseconds) that have elapsed since January 1, 1970, 00:00:00 UTC (the Unix epoch).
Unix timestamps are widely used in computer systems because they provide a simple, standardized way to represent dates and times. They're timezone-independent (always UTC), easy to sort and compare, and compact to store. This makes them ideal for APIs, databases, log files, and any application that needs to work with dates programmatically.
Read more about Complete Guide to Unix Timestamps: Conversion, Best Practices, and Common Use Cases
Seconds vs Milliseconds
Seconds (10 digits): The traditional Unix timestamp format uses seconds since the epoch. A 10-digit number like 1609459200 represents January 1, 2021, 00:00:00 UTC. This format is common in Unix/Linux systems, many APIs, and older systems.
Milliseconds (13 digits): Modern systems, especially JavaScript and many web APIs, use milliseconds since the epoch. A 13-digit number like 1609459200000 represents the same moment but with millisecond precision. JavaScript's Date.now() and getTime() methods return milliseconds.
Our converter automatically detects whether you're entering seconds or milliseconds based on the number of digits, but you can also manually select the unit.
Common Use Cases
- API Development: Many REST APIs use Unix timestamps for date fields because they're unambiguous and easy to parse
- Database Storage: Storing dates as Unix timestamps is efficient and allows easy sorting and querying
- Log Files: Log entries often include Unix timestamps for precise time tracking
- Cache Expiration: Unix timestamps are perfect for setting cache expiration times
- Event Scheduling: Applications use Unix timestamps to schedule future events
- Data Analysis: Time-series data analysis often works with Unix timestamps
- Cross-Platform Compatibility: Unix timestamps work consistently across different operating systems and programming languages