How to use this developer tool
- Enter a Unix value or date string.
- Select the unit or use automatic detection.
- Provide an IANA timezone for an additional display.
- Copy the conversion report.
#077 · Time & Date Tools Developer Tool
Unix Timestamp Converter
Convert Unix timestamps in seconds or milliseconds to UTC, local, ISO 8601, RFC, SQL, and relative-time formats.
Developer Input
Time & Date ToolsAd space
What this developer tool does
The converter normalizes the input to milliseconds and produces common date formats and programming-language examples.
Detect seconds, milliseconds, or date input → normalize to Date → format UTC, local, ISO, RFC, SQL, and Unix units.
Very large microsecond or nanosecond values require BigInt handling and may exceed JavaScript Date limits.
Example
The input 1783742400 is interpreted as Unix seconds and converted to readable date formats.
Tips for better output
- Ten-digit values are usually seconds.
- Thirteen-digit values are usually milliseconds.
- Use UTC for server logs and cross-system comparisons.
FAQ
How do I convert a Unix timestamp to a readable date?
Interpret the timestamp as seconds or milliseconds and format the resulting Date.
How do I tell whether a timestamp uses seconds or milliseconds?
Ten-digit modern values are commonly seconds and thirteen-digit values are commonly milliseconds.
How do I convert a date to Unix seconds?
Parse the date and divide its millisecond value by 1000.
Can Unix timestamps represent dates before 1970?
Yes. Negative Unix timestamps represent dates before the Unix epoch.
How do I convert a Unix timestamp to ISO 8601?
Create a Date from the timestamp and call its ISO formatting method.
Related developer tools
Output formats
| Format | Use |
|---|---|
| ISO 8601 | APIs and storage |
| RFC / HTTP date | Web protocols |
| SQL datetime | Database display |