Unix Timestamp Explained - What It Is and How to Convert It

What is a Unix Timestamp?

A Unix timestamp (also known as Epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC. This date is known as the "Unix Epoch."

Example

• 0 = January 1, 1970, 00:00:00 UTC
• 1000000000 = September 9, 2001, 01:46:40 UTC
• 1710547200 = March 16, 2024, 00:00:00 UTC

Why Use Unix Timestamps?

1. Universal - No timezone confusion. A timestamp means the same thing everywhere
2. Sortable - Simple numeric comparison for ordering events
3. Compact - A single integer vs. a formatted date string
4. Language-agnostic - Every programming language can handle integers

Common Operations

JavaScript

// Current timestamp (seconds)
Math.floor(Date.now() / 1000);

// Timestamp to Date
new Date(timestamp * 1000);

// Date to timestamp
Math.floor(new Date('2026-03-16').getTime() / 1000);

Python

import time
from datetime import datetime

# Current timestamp
time.time()

# Timestamp to datetime
datetime.fromtimestamp(1710547200)

# Datetime to timestamp
datetime(2026, 3, 16).timestamp()

The Year 2038 Problem

Unix timestamps stored as 32-bit signed integers will overflow on January 19, 2038. Modern systems use 64-bit integers, which won't overflow for another 292 billion years.

Milliseconds vs Seconds

• Unix timestamp (seconds): 1710547200 (10 digits)
• JavaScript timestamp (milliseconds): 1710547200000 (13 digits)

If a timestamp has 13 digits, it's in milliseconds. Divide by 1000 to get seconds.

Convert Timestamps Now

Use our free Unix Timestamp Converter to convert between Unix timestamps and human-readable dates instantly.