Unix Timestamp Converter

Convert a Unix timestamp to a readable date, or a date to a Unix timestamp, in seconds and milliseconds.

Current Unix timestamp
0

Seconds since January 1, 1970, UTC. Updates every second.

Timestamp to date

Date to timestamp

What a Unix timestamp is

A Unix timestamp counts the number of seconds that have passed since midnight UTC on January 1, 1970, known as the Unix epoch. It is a single number rather than a calendar date, which is why it is used throughout databases, APIs, log files and programming languages: a plain integer sorts and compares correctly without any date-parsing logic, and it carries no time zone ambiguity on its own. For example, the timestamp 1700000000 converts to Tuesday, Nov 14, 2023, 10:13 PM UTC (your device shows the same instant in your own local time zone instead).

Seconds or milliseconds?

Most systems use seconds, but JavaScript's own Date object and many web APIs use milliseconds instead, which is the same value multiplied by 1,000. The converter above detects which one you have entered: a 10-digit number is treated as seconds, and a 13-digit number is treated as milliseconds, since the two ranges do not overlap for any date in the last 50 years or the next 250.

Why the result depends on time zone

The timestamp itself has no time zone; it is simply a count of seconds. Converting it to a calendar date and clock time is what introduces a time zone, since the same instant reads as a different local time in different places. This tool shows both your device's local time and the UTC equivalent side by side, so there is no ambiguity about which one a given system expects.

Common questions

It was chosen as a practical, round starting point when Unix was developed in the early 1970s, close enough to the system's creation to keep the numbers small at the time, with no deeper technical reason behind that specific date.
Yes. A negative value represents a date before January 1, 1970. Most systems handle this correctly, though some older or 32-bit implementations do not support dates before the epoch.
Systems that store a Unix timestamp as a signed 32-bit integer will overflow on January 19, 2038, since that is the largest date the format can hold. This is known as the Year 2038 problem. Modern 64-bit systems use a larger integer and are not affected.
No. Unix time ignores leap seconds and assumes every day is exactly 86,400 seconds, which keeps the arithmetic simple at the cost of drifting very slightly from true astronomical time. This is standard behavior across virtually all systems that use Unix timestamps.

Continue with

All tools
Time Zone Convert a time between any two time zones, DST handled automatically. Countdown A live countdown to any date and time, updating every second. Date Difference Days, weeks, months and years between two dates. Days From Today Add or subtract days, weeks, months or years.