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Utilboxes

Timestamp Converter

Paste a Unix timestamp to see the date in UTC, in your local time zone and in ISO 8601 form; ten digits are read as seconds and thirteen as milliseconds. Unix time counts seconds since 1 January 1970 UTC. The reverse panel turns a date back into a timestamp, and a live clock shows the current epoch time.

Runs entirely in your browser

Updated

How to use the Timestamp Converter

  1. 1Paste a timestamp in seconds or milliseconds; the unit is detected automatically.
  2. 2Read the date in UTC, in your local timezone, and in ISO 8601 form.
  3. 3Use the reverse panel to turn a date into a timestamp.
  4. 4The live clock shows the current epoch time, which you can copy.

How it works

Unix time counts the seconds since 1 January 1970 UTC, ignoring leap seconds. Because it has no timezone of its own, the same timestamp means the same instant everywhere — which is exactly why it is used for storage and for APIs.

Seconds and milliseconds are told apart by magnitude. A ten-digit number is seconds, a thirteen-digit number is milliseconds. The tool detects this and says which it assumed, so you can override it when working with a system that uses microseconds.

Both readings are always shown together, because the gap between them is where bugs live. A timestamp that reads 23:30 on the 5th in UTC may be 00:30 on the 6th where you are — a different date, from the same number.

The 2038 problem is worth a mention: systems storing Unix time in a signed 32-bit integer overflow on 19 January 2038. Modern platforms use 64-bit values and are unaffected, but the limit still turns up in older data.

Everything runs in this page. Nothing you paste is transmitted, logged or stored, which is what makes it safe to drop a production payload in here while you are debugging.

Worked example

Decoding a timestamp from a log file

  1. Paste 1788604200.
  2. Ten digits, so it is read as seconds.

Result: Saturday, 5 September 2026, 10:30:00 UTC — shown alongside the same instant in your local timezone.

Tips and common mistakes

  • Count the digits: ten means seconds, thirteen means milliseconds.
  • Store times in UTC and convert to local time only for display.
  • Compare the UTC and local readings when a date looks one day out.
  • Use ISO 8601 format, such as 2026-10-01T09:30:00Z, when writing dates in logs and APIs.

Frequently asked questions

What is a Unix timestamp?
The number of seconds since midnight UTC on 1 January 1970. It identifies an instant without reference to any timezone.
Seconds or milliseconds?
Ten digits means seconds, thirteen means milliseconds. JavaScript uses milliseconds; most databases and Unix tools use seconds.
Why is my date one day out?
You are probably comparing UTC with local time. A timestamp late in the UTC day falls on the following day in eastern timezones. Both are shown side by side for that reason.
What is the year 2038 problem?
Signed 32-bit storage of Unix time overflows on 19 January 2038. Modern systems use 64-bit values, but legacy data and embedded devices can still be affected.
How do I get the current Unix timestamp in code?
In JavaScript, Math.floor(Date.now() / 1000). In Python, int(time.time()). On Linux or macOS, date +%s in a terminal.
What is ISO 8601?
The international standard for writing dates and times, such as 2026-10-01T09:30:00Z, where Z means UTC. It sorts correctly as text and is unambiguous.
Do Unix timestamps count leap seconds?
No. Unix time ignores leap seconds, so every day is treated as exactly 86,400 seconds.

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