Unix Timestamps Explained: What They Are and How to Use Them

When you see a number like 1747305600in a database or API response, that's a Unix timestamp — the number of seconds elapsed since January 1, 1970, 00:00:00 UTC (the Unix Epoch). Here's everything you need to know.

Why Unix Timestamps Exist

Dates are complex — timezones, daylight saving time, calendar systems, and locale formatting all add complications. A Unix timestamp is timezone-agnostic and locale-agnostic: a single integer that represents the same moment in time everywhere on Earth.

Seconds vs Milliseconds

Unix timestamps in secondsare typically 10 digits (e.g., 1747305600). JavaScript's Date.now() returns milliseconds — a 13-digit number. Always check which one an API expects — confusing the two causes dates 1000× off.

Converting Timestamps

// JavaScript
new Date(1747305600 * 1000).toISOString()
// → "2025-05-15T08:00:00.000Z"

// Get current timestamp in seconds
Math.floor(Date.now() / 1000)

// Python
import datetime
datetime.datetime.fromtimestamp(1747305600)

The Year 2038 Problem

32-bit signed integers can store Unix timestamps up to 2,147,483,647 — which corresponds to January 19, 2038. Systems using 32-bit timestamps will overflow on that date, wrapping back to 1970. Modern systems use 64-bit integers, which extend the range to 292 billion years.

Convert timestamps instantly with our Timestamp Converter.