Convert a Unix timestamp to a readable date

How to read a Unix timestamp

A Unix timestamp counts the seconds since midnight UTC on 1 January 1970. It carries no timezone, no daylight saving rule, and no formatting — which is exactly why systems store time that way and why it is unreadable at a glance.

The awkward part is not the conversion, it is the unit. The same instant can be written four different ways depending on the precision a system needs, and the only clue is how long the number is:

• 1784563200 — 10 digits, seconds. What most APIs and Unix tools return.
• 1784563200000 — 13 digits, milliseconds. What JavaScript's Date.now() gives you.
• 1784563200000000 — 16 digits, microseconds. Common in Postgres and tracing tools.
• 1784563200000000000 — 19 digits, nanoseconds. Go's UnixNano(), and most metrics pipelines.

Getting this wrong is the single most common timestamp bug: read milliseconds as seconds and your date lands in the year 58,500; read seconds as milliseconds and it lands three weeks after the epoch, in January 1970. Both are obviously wrong once rendered, which is the fastest way to catch the mistake.

Common questions

What is a Unix timestamp?

A Unix timestamp is the number of seconds that have elapsed since 1 January 1970 at 00:00:00 UTC, a moment known as the Unix epoch. Because it is a single integer with no timezone attached, it is unambiguous everywhere in the world, which is why almost every database, log file, and API uses it internally.

Is my timestamp in seconds or milliseconds?

Count the digits. A timestamp of current dates is 10 digits in seconds, 13 in milliseconds, 16 in microseconds, and 19 in nanoseconds. This converter counts them for you and picks the unit automatically, so you can paste a value without knowing which one you have.

Why does the date I get back look wrong by a few hours?

You are almost certainly comparing a UTC reading against your local clock. A timestamp has no timezone of its own, so the same value renders as a different wall-clock time depending on where you read it. This page shows UTC and your local time side by side so the offset is visible rather than surprising.

What is the year 2038 problem?

Systems that store Unix time in a signed 32-bit integer run out of room on 19 January 2038, when the value exceeds 2,147,483,647 and wraps around to a negative number, reading as 1901. Modern systems use 64-bit integers and are unaffected for roughly 292 billion years.

Does anything I paste get uploaded?

No. The conversion runs entirely in your browser using built-in date functions. Nothing is sent to a server, logged, or stored, and the page works offline once loaded.