Unix Timestamp Converter
Conversion
Convert with explicit units, definitions and assumptions.
Formula
Unix seconds = milliseconds since 1970-01-01T00:00:00Z / 1000
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Unix/POSIX time does not represent leap seconds.
Example Calculation
Example inputs
- Direction: UTC date to timestamp
- UTC date or Unix seconds: 1970-01-01T00:00:00Z
1970-01-01T00:00:00Z corresponds to Unix timestamp 0.
Frequently asked questions
How do I use this calculator?
Enter direction, utc date or unix seconds. The result updates automatically. Use Reset to restore the example values.
What method does it use?
Unix seconds = milliseconds since 1970-01-01T00:00:00Z / 1000. Unix/POSIX time does not represent leap seconds.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.