Unix Epoch Converter - Timestamp to Date Calculator

Convert Unix epoch timestamps to human-readable dates and vice versa. Supports both seconds and milliseconds precision.

💡 Auto-detects seconds (10 digits) vs milliseconds (13 digits)
Seconds: 1773407978
Milliseconds: 1773407978937

What is Unix Epoch Time?

Unix epoch (or Unix time) is a system for tracking time as a running count of seconds since January 1, 1970 at 00:00:00 UTC. This moment is called the "epoch." It's the universal standard for representing time in computers, databases, and APIs.

Seconds vs Milliseconds

  • Seconds (10 digits): Standard Unix timestamp. Example: 1706187600
  • Milliseconds (13 digits): JavaScript-style. Example: 1706187600000

JavaScript's Date.now() returns milliseconds, while most Unix utilities and databases use seconds.

Common Operations

  • Get current epoch: date +%s (Linux)
  • Convert epoch to date: date -d @1706187600
  • JavaScript: new Date(epoch * 1000)
  • Python: datetime.fromtimestamp(epoch)

Y2K38 Problem

32-bit systems store epoch time as a signed integer, which overflows on January 19, 2038. Most modern systems use 64-bit timestamps, which won't overflow for billions of years.

Use Cases

  • Database timestamps
  • API request/response times
  • Log file timestamps
  • JWT token expiration
  • Cache invalidation