CODDY Tool

Timestamp Converter

Convert Unix timestamps to dates and back, in any unit.

Turn a Unix timestamp into a readable date in UTC and your local time zone, or convert a date back into a timestamp. The unit is detected automatically, so a value in milliseconds does not land you in 1970.

Everything you enter stays in this browser tab. Nothing is sent to our servers, logged or stored.

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What Timestamp Converter supports

Convert

  • Timestamp → date
  • Date → timestamp
  • Current timestamp

Units

  • Seconds
  • Milliseconds
  • Microseconds
  • Nanoseconds

About Timestamp Converter

A Unix timestamp counts the time since 1 January 1970 UTC, which makes it compact, unambiguous about time zones, and completely unreadable. Converting one is something developers do several times a day while reading logs and API responses.

The recurring trap is unit ambiguity. A bare number is seconds in most Unix tooling, milliseconds in JavaScript, and occasionally microseconds or nanoseconds in tracing systems. Guessing wrong puts you in 1970 or somewhere around the year 55000, so the unit is detected from magnitude and always shown — and you can override it.

Alongside the conversion you get the details that usually prompt the next question: the day of the week, the ISO week number, the day of the year, whether it is a leap year, and how long ago it was in plain language.

How to convert a timestamp

  1. Paste a timestamp or a date

    The tool works out which you gave it and converts in the right direction.

  2. Check the detected unit

    Seconds, milliseconds, microseconds or nanoseconds — override it if the guess is wrong.

  3. Read the result

    You get ISO 8601, UTC, your local time zone and a relative description.

  4. Copy what you need

    Every representation can be copied individually.

Which unit is it?

  • 10 digits — seconds. The Unix default, used by most command-line tools and databases.
  • 13 digits — milliseconds. What JavaScript's Date.now() returns.
  • 16 digits — microseconds. Common in tracing and some Python code.
  • 19 digits — nanoseconds. Go's time.UnixNano and several observability systems.

The year 2038 problem

Systems that store a Unix timestamp in a signed 32-bit integer overflow on 19 January 2038, wrapping around to 1901. It is the same class of bug as Y2K and it is still present in older embedded systems and some legacy databases.

Anything using a 64-bit integer is unaffected for practical purposes — that overflows about 292 billion years from now.

Frequently asked questions

Is a Unix timestamp in seconds or milliseconds?

It depends on the source. Unix tooling, databases and most APIs use seconds; JavaScript uses milliseconds. A present-day timestamp is 10 digits in seconds and 13 in milliseconds, which is how this tool detects the unit — and you can override it.

Do timestamps have a time zone?

No, and that is the point. A Unix timestamp is always the number of seconds since 1970 in UTC, which is why it is unambiguous. Time zones only enter when you format it for a human, which is why both UTC and your local time are shown.

Do timestamps account for leap seconds?

No. Unix time deliberately ignores leap seconds, treating every day as exactly 86,400 seconds. This keeps arithmetic simple at the cost of drifting very slightly from astronomical time.

What is the year 2038 problem?

Systems storing a timestamp in a signed 32-bit integer overflow on 19 January 2038 and wrap around to 1901. Anything using 64-bit integers is unaffected for any practical purpose.

What date formats can I paste in?

Anything your browser can parse, which includes ISO 8601 forms like 2026-08-14 and 2026-08-14T09:30:00Z, plus most common written formats. ISO 8601 is the least ambiguous and always the safest choice.

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Timestamp Converter is free to use with no account, no watermark and no usage limits. Last updated 14 August 2026.