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    Development7 min readJanuary 8, 2026

    Unix Timestamps Explained for Developers

    Everything you need to know about the Unix Epoch, how to handle timestamps in different languages, and the looming Year 2038 problem.

    Try the Timestamp Converter

    Put what you learn into practice

    What is a Unix Timestamp?

    A Unix timestamp (or Epoch time) is a system for describing a point in time. It is defined as the number of seconds that have elapsed since 00:00:00 UTC on Thursday, 1 January 1970, minus leap seconds.

    • Example Timestamp: 1767225600 represents Jan 01, 2026.

    It is the standard way computers store and track time because dealing with a single integer is much easier for a CPU than dealing with complex strings like "January 1st, 1970, 12:00 AM".

    Why 1970?

    The date was chosen arbitrarily by Unix engineers Ken Thompson and Dennis Ritchie in the early 70s. They needed a reference start point (the "Epoch"). 1970 was a convenient round number close to when they were developing the system.

    Seconds vs Milliseconds

    One common source of bugs is confusion between seconds and milliseconds.

    • Unix Timestamp (Seconds): 10 digits (e.g., 1767225600) - Used by PHP, Python, Go, MySQL.
    • Javascript Timestamp (Milliseconds): 13 digits (e.g., 1767225600000) - Used by Java, JavaScript.

    Tip: If your date looks like the year 1970 or 52000, you are likely mixing up seconds and milliseconds!

    Handling Timestamps in Code

    Here is how to get the current timestamp in popular languages:

    JavaScript / TypeScript

    // Milliseconds (13 digits)
const nowMs = Date.now(); 

// Seconds (10 digits)
const nowSec = Math.floor(Date.now() / 1000);

    Python

    import time
# Seconds (float)
now = time.time()
# Seconds (int)
now_int = int(time.time())

    PHP

    echo time(); // Seconds

    Go

    import "time"
now := time.Now().Unix() // Seconds

    The Year 2038 Problem

    Similar to the Y2K bug, the Year 2038 problem (Y2038) relates to how computers store time.

    Many older systems store the Unix timestamp as a signed 32-bit integer.

    • Max value of 32-bit int: 2,147,483,647.
    • This corresponds to January 19, 2038 @ 03:14:07 UTC.

    One second after this, the integer will overflow, wrapping around to -2,147,483,648, which corresponds to December 13, 1901. This will cause critical failures in databases, file systems, and software that relies on 32-bit time.

    Solution: Most modern systems (64-bit architecture) store time as a 64-bit integer, which won't run out for 292 billion years.

    Timezones? What Timezones?

    The beauty of the Unix timestamp is that it is Timezone Agnostic. 1767225600 is the exact same moment in time in London, Tokyo, and New York.

    Timezones only matter when you convert that number into a human-readable string.

    • In UTC: 00:00:00
    • In NY (EST): 19:00:00 (Previous day)

    Best Practice: Always store time as UTC (or Unix Timestamp) in your database. Only convert to a local timezone when displaying it to the user.

    Conclusion

    The Unix Timestamp is a fundamental concept in computing. Understanding the difference between seconds vs. milliseconds and UTC vs. Local Time is essential for every developer.

    Use our Timestamp Converter to quickly verify your timestamps and debug date logic.

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