Date & time

Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and back. Seconds or milliseconds, ISO 8601, UTC, local — all in one place.

Unix → Date

Unix timestamp

Unit

Seconds Milliseconds

Quick picks

Now Epoch (1970) Y2K (2000) Y2038

Decoded date

ISO 8601—

UTC—

Local—

Relative—

Timezone—

Date → Unix

Date and time

Encoded timestamp

Unix (s)—

Unix (ms)—

ISO 8601—

UTC—

About Unix timestamps

A Unix timestamp is the number of seconds elapsed since 00:00:00 UTC on 1 January 1970, the so-called Unix epoch. Many APIs, log files and databases store dates this way because it's a single integer with no timezone, calendar or locale ambiguity. Some systems use milliseconds (the JavaScript Date.getTime() default), giving values roughly 1000× larger than the seconds form. Converting between a timestamp and a wall-clock date requires applying a timezone offset; this tool decodes into both UTC and your browser's local zone.

How to use this converter

Paste a Unix timestamp into the top box and pick the unit (seconds is the default; switch to milliseconds for 13-digit JS timestamps). The decoded panel shows ISO 8601, the standard UTC string, your local time, a relative phrase like 3 days ago, and the components broken out year by year. The bottom panel does the inverse — pick a date and time, and read off the corresponding Unix seconds, Unix milliseconds, ISO 8601 and UTC values. Hit Use current time to populate it with right-now in one click.

Common timestamps

A few values worth knowing: 0 is the Unix epoch itself, 946684800 is midnight 1 January 2000 UTC (Y2K), 1234567890 is 13 February 2009 23:31:30 UTC (popular for tests), and 2147483647 is 19 January 2038 03:14:07 UTC — the moment when 32-bit signed timestamps overflow. Modern systems use 64-bit timestamps and are unaffected, but legacy databases and embedded firmware may still need patching before that date.

Frequently asked questions

Why are some timestamps 10 digits and others 13?

Ten-digit timestamps are seconds since the epoch and are the classic Unix form, used by most system APIs, databases and protocols. Thirteen-digit timestamps are milliseconds — JavaScript's Date.getTime(), Java's System.currentTimeMillis(), and many web APIs return this. If a number is around 1.7e9 it's seconds; around 1.7e12 it's milliseconds.

What is ISO 8601?

ISO 8601 is the international standard for date and time strings — 2024-03-15T14:30:00.000Z. The T separates date and time, and the trailing Z means UTC ("Zulu time"). It sorts correctly as a plain string, parses identically across languages, and is the format most modern APIs prefer over Unix timestamps when human-readability matters.

Does the local time depend on my computer?

Yes. The browser uses your operating-system timezone to render the local string. If your clock or timezone is wrong, the local output and the relative phrase will be wrong too — UTC and ISO 8601 stay correct because they're absolute. Travelling? Set your OS to Auto for it to track location, or pick the right zone manually.

What is the Y2038 problem?

Many older Unix systems store timestamps as 32-bit signed integers, which overflow at 2,147,483,647 seconds — 03:14:07 UTC on 19 January 2038. After that point, affected systems can wrap around to 1901. Most current operating systems, languages and databases moved to 64-bit time long ago, but you'll still find 32-bit time in embedded firmware, old kernels and legacy file formats.

Are leap seconds handled?

No, and almost no Unix system handles them either. Unix time pretends every day is exactly 86,400 seconds long. Leap seconds are inserted into UTC by smearing or stepping at the operating-system level — the timestamp itself doesn't reflect them. For everyday use this is invisible; for high-precision timing (financial trading, scientific instruments) you need a different time scale like TAI.

Can I share a link with a specific timestamp?

Not yet — input is purely client-side and not encoded into the URL. To share a timestamp, copy the number and paste it into a chat or document; recipients can paste it back here. If you need shareable links for time-zone meeting planning, dedicated tools like Every Time Zone are a better fit.

Unix Timestamp Converter