About the Unix Timestamp Converter
Convert Unix Epoch Seconds and Milliseconds — Convert numeric Unix timestamps into readable UTC ISO dates and compare second-based and millisecond-based values.
Formula or method
Unix time counts elapsed time since 1970-01-01 00:00:00 UTC. Seconds are multiplied by 1,000 to obtain JavaScript milliseconds.
Worked example
A timestamp of 0 seconds converts to 1970-01-01T00:00:00.000Z; 1,000 milliseconds is one second.
How to use the tool
- Paste a numeric timestamp.
- Choose seconds or milliseconds.
- Read the UTC ISO date and equivalent timestamps.
Common uses
API debugging, logs, data exports.
Assumptions and limitations
The tool does not account for leap seconds and uses JavaScript Date's supported range. UTC ISO output is not a local time display.
Frequently asked questions
How do I know if a timestamp is seconds or milliseconds?
Many modern APIs use 10-digit seconds and 13-digit milliseconds, but check the source documentation instead of guessing.
Privacy and support
Your inputs are processed locally in your browser. ToolMosaic does not upload or store the values you enter in this tool. Our tools are free, and we appreciate your support.