Time & Scheduling

Unix Timestamp Converter

Convert Unix seconds and milliseconds to local or UTC ISO dates, and convert ISO dates back to timestamps.

Runs locally in your browser

Timestamp unit

Input value

Quick examples

Input is valid

How to use

Choose an input type, then paste a timestamp or an ISO 8601 date. Timestamp values are automatically classified as seconds or milliseconds by magnitude; zone-less ISO dates can be interpreted as local time or UTC.

Frequently asked questions

How are seconds and milliseconds detected?

Auto mode treats an absolute value below 100 billion as seconds and a larger value as milliseconds. You can also choose a unit explicitly when a boundary value is ambiguous.

Which timezone does the local ISO date use?

The local ISO result uses your browser’s current timezone and includes its numeric offset, such as +08:00. UTC results always end with Z.

Can dates before 1970 be converted?

Yes. Dates before the Unix epoch use negative timestamps. For example, -1 second is 1969-12-31T23:59:59Z.