Unix Timestamp Converter

A Unix timestamp (also called Unix epoch time) represents the number of seconds elapsed since January 1, 1970, 00:00:00 UTC — the 'Unix epoch'. Because any point in time can be expressed as a single integer, timestamps are widely used in programs, databases, API responses, and log files for exchanging time data between systems in a language-agnostic and timezone-independent way. Two variants exist: seconds (10 digits, e.g. 1714000000) and milliseconds (13 digits, e.g. 1714000000000), and the unit can be auto-detected from the digit count.

Common Time Format Comparison

Unix timestamps in seconds are simple integers like 1714000000. The millisecond variant adds three digits: 1714000000000. ISO 8601 format (2024-04-25T03:26:40.000Z) is the international standard and includes full timezone information. RFC 2822 format is used in email headers. Japan Standard Time (JST) is UTC+9, so UTC 03:26:40 becomes JST 12:26:40. Note that the year 2038 problem (Y2K38) affects systems storing Unix timestamps as a signed 32-bit integer — the maximum value of 2,147,483,647 corresponds to January 19, 2038. Modern systems use 64-bit integers, which extend the range far beyond any practical concern. When working with international systems, always clarify whether a timestamp is in seconds or milliseconds, and whether it represents UTC or a local timezone.

Common Use Cases

Inspect timestamp fields in JSON API responses, analyze timestamps in log files, verify Unix timestamps stored in a database, calculate deadlines like '7 days from now' or '30 days ago', and check token expiry times (the exp claim in JWTs). The Unix epoch is also used internally by programming languages: JavaScript's Date.now() returns milliseconds, Python's time.time() returns seconds as a float, and Go's time.Unix() accepts seconds and nanoseconds. When debugging an API that returns a suspicious timestamp, paste it here to immediately see the human-readable date and relative time. Timestamp conversion is an everyday task for backend developers, DevOps engineers, and anyone who works with APIs or distributed systems.