Unix timestamp converter
Convert Unix timestamps to human-readable dates and dates back to epoch time in your browser. Handles seconds and milliseconds with UTC, local time, and ISO 8601 output.
The converter runs entirely in your browser using its built-in date engine. The timestamps and dates you enter stay in this tab and are not sent to Calculation Hub.
Analytics events, when you have allowed analytics cookies, record only the action name, tool slug, and category. They do not include the timestamps or dates you convert.
Do not enter production secrets into any web page unless you are allowed to handle them there. This tool avoids uploads, but your browser, extensions, and device policies still matter.
Good for
Read an epoch value from a log file or database column.
Decode iat and exp claims while debugging a JSON Web Token.
Turn a calendar date into a timestamp for an API request.
Not for
It does not adjust for historical daylight saving rule changes.
It does not account for leap seconds, which Unix time ignores.
It does not store a history of past conversions.
Additional Resources
Frequently Asked Questions
What is a Unix timestamp?
A Unix timestamp is the number of seconds since 00:00:00 UTC on January 1, 1970, called the Unix epoch. It is a single, time-zone-independent number that represents a precise moment in time, which is why software uses it to store and exchange dates.
How do I tell seconds and milliseconds apart?
A current seconds timestamp has about 10 digits, while a milliseconds timestamp has about 13. The converter auto-detects the unit by magnitude, but you can force seconds or milliseconds with the unit selector if your value is unusual.
Does a Unix timestamp depend on time zones?
No. The number is always measured against UTC, so it is identical everywhere. Time zones only matter when you display the instant, which is why the converter shows UTC, your local time, and an ISO 8601 string side by side.
How do I convert a date back into a timestamp?
Switch to the Date to Timestamp tab, enter the date and time, and choose whether it should be read as your local time or as UTC. The converter returns the equivalent seconds and milliseconds along with an ISO 8601 string.
Can it handle dates before 1970 or impossible dates?
Yes. Moments before the epoch return negative timestamps, and impossible inputs such as February 30 or minute 99 are rejected with a clear message instead of silently rolling over.