Unix timestamps are widely used by computers, websites and applications to represent dates and times as a single number.
Instead of storing a date like 1 October 2026, 3:00 PM, a Unix timestamp stores the number of seconds that have passed since a fixed starting point.
In this guide, you’ll learn what Unix timestamps are, how they work, and how to convert a Unix timestamp into a readable date and time.
How to Convert Unix Timestamps: A Simple Step-by-Step Guid
By ToolNestPro | Updated September 2026
What Is a Unix Timestamp?
A Unix timestamp is a number that represents the amount of time that has passed since:
1 January 1970 at 00:00:00 UTC
This starting point is known as the Unix Epoch.
For example:
0
represents:
1 January 1970 at 00:00:00 UTC
As time passes, the number increases, making Unix timestamps useful for storing and comparing dates in software, databases, APIs and web applications.
How to Convert a Date to a Unix Timestamp
To convert a Unix timestamp into a readable date and time, the timestamp is interpreted as the number of seconds that have passed since the Unix Epoch.
For example:
1609459200
converts to:
1 January 2021 at 00:00:00 UTC
This makes it easier to understand timestamps stored in databases, APIs, logs and applications.
A Unix timestamp converter can do this instantly, so you do not need to calculate the date manually.
How to Convert a Unix Timestamp to a Date
You can also convert a normal date and time into a Unix timestamp.
For example:
1 January 2021 at 00:00:00 UTC
converts to:
1609459200
This is useful when a website, API or application requires dates to be stored or sent as Unix timestamps instead of normal calendar dates.
When converting dates to Unix timestamps, the time zone matters. Unix timestamps are based on UTC, so local time may need to be adjusted before converting.
Common Unix Timestamp Mistakes
Unix timestamps are simple, but a few common issues can cause incorrect dates or confusing results.
Common mistakes include:
confusing seconds with milliseconds
using the wrong time zone
converting local time without adjusting for UTC
copying an incomplete timestamp
using an incorrect date format before conversion
A standard Unix timestamp is usually measured in seconds, while some systems use milliseconds.
For example:
1609459200
is in seconds, while:
1609459200000
is the same moment represented in milliseconds.
Checking the format before converting can help avoid incorrect results.
Unix Timestamp vs Regular Date and Time
A regular date and time is designed to be easy for people to read, for example:
1 October 2026 at 8:00 PM
A Unix timestamp is designed to be easy for computers to store, compare and process, for example:
1790881200
The main difference is that a Unix timestamp stores time as a number, while a regular date uses a calendar format.
Unix timestamps are commonly used in:
databases
APIs
server logs
web applications
software systems
This makes them useful when different systems need to exchange date and time information consistently.
Convert Unix Timestamps Online
Need to convert a Unix timestamp into a readable date and time, or turn a date into a Unix timestamp?
Use our free Unix Timestamp Converter to convert between Unix timestamps and normal dates quickly online.
A Unix timestamp represents the number of seconds that have passed since 1 January 1970 at 00:00:00 UTC.
Why do some Unix timestamps have 10 digits and others 13 digits?
A 10-digit timestamp is usually measured in seconds, while a 13-digit timestamp is usually measured in milliseconds.
Are Unix timestamps affected by time zones?
The timestamp itself is based on UTC. Time zones are applied when the timestamp is converted into a local date and time.
Frequently Asked Questions
What does a Unix timestamp represent?