FW Fawran.tools

Unix Timestamp: Why Computers Represent Time as a Weird Number Like 1735689600

1735689600 1 Jan 2025, 00:00

Opened an API response and found the date represented as a long number like 1735689600 with no clarity at all? That's a Unix timestamp — the computer's preferred way of representing time, and understanding it is simple once you know the core idea.

What is a Unix timestamp?

A Unix timestamp is a number representing how many seconds have passed since a specific starting moment: midnight on January 1, 1970, UTC (called the "Unix Epoch"). This means any moment in time, past or future, can be represented by one simple number.

Why do systems prefer a number over a readable date?

Numbers are far easier to compare and do math with than dates written as text. Knowing that one event happened before another simply means comparing two numbers, instead of parsing complex date text in different formats. The number is also time-zone independent, making it easier to handle data from users in different countries.

The year 2038 problem

Legacy systems storing the timestamp as a 32-bit number (instead of the modern 64-bit) will hit the maximum storable value on January 19, 2038. After that date, the number may "overflow" and wrap around to a negative or completely wrong value, similar to the famous "Y2K" problem at the turn of the millennium. Modern systems use 64-bit and are safe from this issue for millions of years to come.

Common uses

How to convert between them easily

Using the Unix Timestamp Converter on Fawran Tools:

  1. Paste a timestamp number to convert it to a readable date and time.
  2. Or pick a date and time to convert them to the corresponding timestamp.
  3. Get the result instantly, ready to copy.
Try the Unix Timestamp Converter now
Instant conversion in both directions, locally in your browser
Open the tool

Frequently asked questions

What's the exact date counting starts from?

Counting starts from midnight on January 1, 1970, UTC, called the "Unix Epoch."

Does the number differ by time zone?

No, the timestamp is a globally unified number unaffected by time zone; conversion to local time happens only at display.

What is the year 2038 problem?

Legacy 32-bit systems hit the max value in January 2038; modern 64-bit systems are free of this issue.

Is there a difference between seconds and milliseconds?

Yes, some systems use milliseconds, making the number 1000 times larger. Confirm the unit before converting.

Conclusion

A Unix timestamp isn't a random strange number — it's a unified, simple system for representing time independent of time zone, and understanding it makes reading any API response or database record with dates in this format much easier.

Advertisement