Unix Timestamp Converter
Convert between Unix timestamps (seconds or milliseconds) and ISO 8601 dates in both directions.
A Unix timestamp counts the number of seconds elapsed since the epoch—January 1, 1970 at 00:00 UTC. It is the standard way to store time in logs, databases, and APIs because it is unambiguous and independent of time zone.
Some systems use milliseconds instead of seconds, giving a 13-digit number instead of 10. Millisecond precision is common in JavaScript runtimes, Java, and databases such as PostgreSQL when they expose epoch values. Both fields stay synchronized as you type, so you can tell which unit a pasted value uses without mental arithmetic.
Dates written as text come in countless regional formats, which is why APIs standardize on ISO 8601 — the 2026-08-11T12:00:00Z notation. Converting a timestamp to ISO 8601 and back lets you paste log values into queries, tickets, and reports without anyone misreading the month and day order.
Common uses
- Decoding an exp claim from a JWT or an API error into a human-readable date.
- Building a query against a log system that expects epoch milliseconds.
Frequently asked questions
- Is the timestamp in seconds or milliseconds?
- A 10-digit number is seconds (current epoch); a 13-digit number is milliseconds. This tool converts both at once.
- Why is 1970 the start?
- January 1, 1970 was chosen as the Unix epoch by the designers of the operating system in the late 1960s and has since been adopted widely as a portable reference point.
- Will timestamps run out in 2038?
- The old 32-bit signed integer limit causes a rollover on January 19, 2038. Modern systems use 64-bit integers, which have no practical limit for thousands of years.
- What is the current timestamp?
- The panel at the top of the tool shows the live Unix timestamp in seconds, updating once per second. Press 'Use current time' to load it into the conversion fields and read the matching ISO 8601 date and local time.