Unix Timestamp Converter

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 the universal standard for tracking time in computers, databases, and APIs because it is timezone-independent and easy to compare mathematically. JavaScript uses millisecond timestamps (13 digits) while most backend systems and databases use second timestamps (10 digits).

How to Use This Tool

• Select whether your timestamp is in seconds (10 digits) or milliseconds (13 digits)
• Enter a Unix timestamp or click Now to insert the current time
• Use Detect if you are unsure whether the value is seconds or milliseconds
• Use Auto-convert to update outputs as you type, or switch it off for manual conversion
• Click Convert to see the result in ISO 8601, UTC, timezone-adjusted display, and relative time
• Copy any individual format using the per-field copy buttons
• Use the Date / ISO panel to convert human-readable date strings back to Unix time
• Use Batch Convert to process multiple timestamps in one action and download CSV output

Common Use Cases

• Debugging API responses that return epoch timestamps
• Converting between JavaScript millisecond timestamps and Unix second timestamps
• Checking when a JWT token or session expires
• Verifying database timestamp values during development
• Converting log file timestamps to human-readable dates

Tips and Common Mistakes

• If your date is in 1970, you are likely passing seconds to a function that expects milliseconds — multiply by 1000
• If your date is in the year 55000+, you are likely passing milliseconds to a function that expects seconds — divide by 1000
• Unix timestamps are always UTC — timezone only matters when displaying the human-readable format
• 32-bit systems will overflow on January 19, 2038 (the Y2038 problem) — use 64-bit timestamps