Why is everything shown in UTC?

Because a Unix timestamp has no time zone. It names an instant, and every zone writes that instant down differently. Showing it in your local zone would make the same timestamp appear to be two different times for two people reading the same log, which is the bug this tool exists to prevent.

What is the year 2038 problem?

Systems that store the timestamp in a signed 32-bit integer run out of room on 19 January 2038, and roll over to 1901. Anything modern uses 64 bits and is fine for another 292 billion years, but embedded devices and old database columns are still out there — which is why a date suddenly reading 1901 is a recognisable symptom rather than a mystery.

Do timestamps account for leap seconds?

No. Unix time pretends every day has exactly 86,400 seconds, so a leap second is absorbed rather than counted. That makes the arithmetic simple and means Unix time is a few dozen seconds behind true elapsed atomic time — which matters for astronomy and almost nothing else.

Timestamp Converter

Convert a Unix timestamp into a date you can read, or a date back into the number your logs and APIs use. Timestamps count from midnight UTC on 1 January 1970, and the usual confusion is whether a number is in seconds or milliseconds — this page detects that from the size of the number and tells you which it assumed, so a log line is never read as a date 47,000 years in the future.

Convert

Unix timestamp

Seconds or milliseconds since 1 January 1970 UTC.

Timestamp is in

Date

Time — UTC, 24 hour

Interpreted as UTC, so the answer doesn't shift with whoever is reading the page.

Result

ISO 8601      2023-11-14T22:13:20.000Z
UTC           2023-11-14 22:13:20 UTC
Date          14 November 2023
Day           Tuesday
Seconds       1700000000
Milliseconds  1700000000000

Read as seconds — detected from the size of the number. Every line is UTC, so it reads the same wherever you are.

Nothing is uploaded — this tool runs inside your browser, so your files never leave your device.

Help us improve

Why use this tool

Converts in both directions — timestamp to date, date to timestamp
Detects seconds versus milliseconds, and says which it used
Shows ISO 8601, a readable UTC date and the day of the week
Everything is UTC, so the answer doesn't change with who is reading it

How it works

1Choose which direction you're converting.
2Type the timestamp, or pick a date and a UTC time.
3Read the result — ISO 8601, plain date, and both seconds and milliseconds.

Timestamp Converter — frequently asked questions

By its length. A current timestamp in seconds is 10 digits; in milliseconds it is 13. Anything above about 100,000,000,000 is milliseconds, because as seconds it would be the year 5138 — that is precisely the rule this page applies when the unit is left on automatic.

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