Question 1

What is a Unix timestamp?

Accepted Answer

Unix timestamp is the number of seconds since January 1, 1970 00:00:00 UTC (Unix Epoch). It's a timezone-independent integer that increases by 1 every second. Used universally in databases, APIs, logs, and file systems for time representation.

Question 2

How do I convert Unix timestamp to date?

Accepted Answer

In JavaScript: new Date(timestamp * 1000) for seconds, new Date(timestamp) for milliseconds. In Python: datetime.fromtimestamp(timestamp). In PHP: date('Y-m-d', timestamp). Online converters like this tool handle both seconds and milliseconds automatically.

Question 3

What is the difference between seconds and milliseconds timestamp?

Accepted Answer

Seconds timestamp: 10-digit integer (e.g., 1704067200). Milliseconds timestamp: 13-digit integer (e.g., 1704067200000). JavaScript Date uses milliseconds internally. Unix/Linux typically uses seconds. Milliseconds provide more precision (dates within same second).

Question 4

Why does Unix timestamp start at 1970?

Accepted Answer

Unix Epoch (1970-01-01) was chosen when Unix was developed in the early 1970s. January 1 makes calculations simpler (month boundaries don't affect day count). Early Unix developers needed a simple, arbitrary starting point. Timestamp 0 represents this epoch.

Question 5

What happens when Unix timestamp exceeds 32-bit integer?

Accepted Answer

32-bit signed integer max is 2147483647 seconds = January 19, 2038. This 'Year 2038 problem' affects older systems. Modern systems use 64-bit integers, extending range to billions of years. Most current systems are already 64-bit and unaffected.

Unix Timestamp Converter

Conversion Results

Common Timestamps

Unix Timestamp Reference

Developer Use Cases