Unix Timestamp Converter

What this does

A Unix timestamp counts the time since 1 January 1970 at midnight UTC. Many systems count in seconds, and JavaScript counts in milliseconds, so the same moment appears as either a 10-digit or a 13-digit number — and mixing the two up is how logs end up showing dates in 1970 or tens of thousands of years in the future.

Paste a number and this tool works out which unit it is most likely in, then shows the moment in UTC, in ISO 8601 format and in your device's own time zone.

How to use it

1. Paste a timestamp, or press Now to use the current time.
2. Check whether the tool read it as seconds or milliseconds, and switch the unit if it guessed wrong.
3. To go the other way, pick a date and time in the second panel and read off the timestamp.

Where it stops being right

• Local times use your device's time zone setting. If that setting is wrong, the local time shown will be wrong too; the UTC time is unaffected.
• The seconds-or-milliseconds guess is based on the size of the number, so a very small millisecond value or a date far in the future can be misread. The unit switch is there for those cases.

Questions

Why does my timestamp show a date in 1970?

It is almost always a seconds value being read as milliseconds, which makes it a thousand times too small. Switch the unit to seconds.

Do Unix timestamps include time zones?

No. A timestamp is the same number everywhere; a time zone only matters when the moment is displayed as a date and time.

What is ISO 8601?

An international standard way of writing dates and times, such as 2026-09-16T08:30:00Z, where the Z means UTC. It sorts correctly as text, which is one reason APIs use it.