Unix Millisecond Converter
Auto-detect 10-digit second and 13-digit millisecond timestamps and convert to date/time.
Category: Date & Time
When to use?
Use it to quickly distinguish and convert 13-digit millisecond timestamps (like JavaScript Date.now()) from 10-digit second timestamps in server logs.
How to use
- Enter a numeric timestamp.
- Check the detected unit and the local/UTC time.
- Enter a date and time to reverse into second and millisecond values.
Input Explanation
Enter an integer timestamp. About 10 digits is detected as seconds, about 13 digits as milliseconds.
Calculation Basis
A Unix timestamp is time elapsed since 1970-01-01 00:00:00 UTC. Second values are multiplied by 1,000 to get milliseconds.
Usage Examples
- Check log times - Safely distinguish mixed second/millisecond timestamps into readable time.
- Interpret Date.now() values - Read a 13-digit millisecond value from JavaScript Date.now() as date and time.
- Reverse a timestamp - Convert a specific date and time into second/millisecond timestamps for code or queries.
Examples
- 1700000000 → detected as seconds
- 1700000000000 → detected as milliseconds
Cautions
- Confirm the unit (seconds vs. milliseconds) before entering to avoid conversion errors.
- Time-zone settings can cause a one-day difference in some cases.
FAQ
How is this different from the timestamp converter?
This focuses on distinguishing seconds/milliseconds and clearly showing Date.now()-style millisecond values.
How are seconds and milliseconds distinguished?
By digit count — about 10 digits is detected as seconds, about 13 digits as milliseconds.
How do I convert seconds to milliseconds?
Multiply seconds by 1,000 for milliseconds, or divide milliseconds by 1,000 for seconds.
Which time zone is the input read in?
A Unix timestamp is an absolute UTC value; results show both your local time zone and UTC.
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