How to use the timestamp converter
Timestamp → date. Paste a Unix timestamp. The tool detects the unit from the number of digits (10 digits for seconds, 13 for milliseconds, 16 for microseconds) and shows the date in your local time zone, in UTC, in ISO 8601 format, and relative to now. If the guess is wrong, choose the unit yourself from the menu.
Date → timestamp. Pick a date and time, then choose whether it should be read as your local time or as UTC. The tool gives the timestamp in seconds and milliseconds.
The current Unix time at the top updates every second. Click Copy next to any value to copy it.
What a Unix timestamp is
A Unix timestamp counts the seconds that have passed since 00:00:00 UTC on 1 January 1970, a moment known as the Unix epoch. Because it is a single number with no time zone, it is the standard way to store and exchange points in time in databases, logs, APIs, and file systems.
0is 1970-01-01T00:00:00Z.1700000000is 2023-11-14T22:13:20Z.- Negative numbers are dates before 1970.
Seconds or milliseconds?
Different systems use different units, and mixing them up is the most common timestamp bug:
- Seconds: Unix and Linux, PHP
time(), Pythontime.time()(with a decimal part), most databases, and JWT claims such asexp. - Milliseconds: JavaScript
Date.now(), JavaSystem.currentTimeMillis(), and many JSON APIs. - Microseconds or nanoseconds: some databases, Go, and high-precision logs.
If a converted date lands in January 1970, a seconds value was probably read as milliseconds. If it lands tens of thousands of years in the future, a milliseconds value was read as seconds.
Time zones
A timestamp itself has no time zone. The time zone only matters when you turn it into a calendar date and clock time. A timestamp that reads 10:00 in London reads 18:00 in Shanghai in winter, but 17:00 in summer, when London is on daylight saving time.
When you convert a date to a timestamp, be explicit. "2026-03-01 09:00" in New York and the same text in UTC are five hours apart. Store timestamps or UTC values, and convert to local time only when you display them.
The year 2038 problem
Systems that store Unix time in a signed 32-bit integer cannot count past 2,147,483,647 seconds, which is 03:14:07 UTC on 19 January 2038. After that, the number overflows to a negative value and dates jump back to 1901. Modern 64-bit systems are not affected, but embedded devices and old database columns still can be.
Frequently asked questions
Does Unix time include leap seconds?
No. Unix time treats every day as exactly 86,400 seconds, so leap seconds are not counted. This is why the conversion to UTC is always a simple calculation.
What is ISO 8601?
An international date format, such as 2026-10-26T14:30:00Z. The Z means UTC. It sorts correctly as text and is the safest format for APIs.