Unix Timestamp Converter

Unix time (also called Epoch time or POSIX time) is a system for describing a point in time. It's defined as the number of seconds that have elapsed since 00:00:00 UTC on January 1, 1970 (the Unix epoch).

Example: The timestamp 1700000000 represents November 14, 2023, 22:13:20 UTC.

Unix timestamps can be expressed in two formats:

• Seconds: Standard Unix time (e.g., 1700000000)
• Milliseconds: Common in JavaScript (e.g., 1700000000000)

To convert: Milliseconds = Seconds × 1000

How to tell them apart: Millisecond timestamps are typically 13 digits long, while second timestamps are 10 digits (for current dates).

Negative timestamps represent dates before January 1, 1970:

• -86400 = December 31, 1969
• -31536000 = January 1, 1969

This allows Unix time to represent historical dates.

On January 19, 2038, at 03:14:07 UTC, 32-bit signed integers will overflow. This is similar to the Y2K problem.

Solution: Use 64-bit integers, which won't overflow for approximately 292 billion years.

The timestamp 2147483647 represents this limit.

Important: Unix timestamps are always in UTC (Coordinated Universal Time).

When you convert a timestamp to a date:

• The timestamp represents a specific moment in time
• That moment is the same everywhere in the world
• But the local time display varies by timezone

Example: Timestamp 1700000000 is:

• 22:13:20 in UTC
• 17:13:20 in New York (EST, UTC-5)
• 07:13:20 next day in Tokyo (JST, UTC+9)

• Logging: Timestamp every log entry
• Databases: Store creation/modification times
• APIs: Include timestamps in responses
• Caching: Set expiration times
• Sessions: Track login and expiry times
• File Systems: File creation and modification times

The batch conversion feature allows you to convert multiple timestamps at once:

• Enter one timestamp per line
• Supports both seconds and milliseconds (auto-detected)
• Useful for processing log files or API responses
• Results show both formats for easy comparison