Unix Timestamp Converter

About this tool

A Unix timestamp represents a moment in time as a single number: the count of seconds that have elapsed since 00:00:00 UTC on January 1, 1970 — a moment developers call "the Unix epoch." It's hard to overstate how much of the software world runs on this one convention. Database timestamp columns, API response fields, log file entries, JWT expiry claims, cache expiration headers — all of it very often boils down to a Unix timestamp underneath, precisely because a single integer is unambiguous, trivially comparable (a later time is always a larger number), and free of the timezone and formatting ambiguity that plain date strings carry.

The most common practical snag is a unit mismatch: some systems and languages express Unix time in whole seconds (the original definition), while others — JavaScript's Date.now() and a large share of web APIs among them — use milliseconds. Paste a millisecond timestamp into a field expecting seconds and you'll get a date a thousand times further in the future or the past than intended, usually landing somewhere absurd like the year 1970 or 50000. This tool detects which unit you've likely entered based on the number of digits and converts accordingly, and shows both interpretations when it's ambiguous.

Timezone handling is the other place Unix timestamps get misunderstood, somewhat ironically, since the entire point of a timestamp is that it has no timezone — it's a fixed point in universal time. The confusion happens at the boundary, when a timestamp is converted to a human-readable date: "1750000000" is a specific instant, but whether that instant reads as "3:00 PM" or "11:00 PM" on the calendar depends entirely on which timezone you're viewing it from. This tool lets you pick the timezone for display explicitly, rather than silently assuming your browser's local timezone, which is what causes a timestamp to look "wrong" when a teammate in a different timezone reports a different local time for the exact same underlying value.

The live clock at the top updates once per second and shows the current moment as a Unix timestamp — useful as a quick reference point, and as a one-click way to grab "right now" as a starting value for testing an API call, a cache TTL, or an expiry field without doing the arithmetic by hand.