When to use this calculator
Convert a civil date at UTC midnight into Unix seconds. Uses UTC midnight, not your local midnight; no time-of-day input is inferred.
Explore the calendar dates & age calculators for other questions in this topic. For a related calculation, use the Day of the Week Calculator: Find the weekday name for a Gregorian calendar date.
PUTTING IT INTO PRACTICE
Date to Unix Timestamp: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| UTC calendar date | 2026-01-01 |
| Result | 1,767,225,600 seconds since epoch |
- Check the input labels and enter the example values above.
- Apply the relationship: Unix seconds = milliseconds from epoch to UTC midnight/1000..
- The result is 1,767,225,600 seconds since epoch, rounded for display.
How to interpret your result
Uses UTC midnight, not your local midnight; no time-of-day input is inferred.
Choose whether an interval includes the start or end boundary. Month and year additions use explicitly stated clamping rules when a destination day does not exist. Date-only arithmetic is kept independent of local daylight-saving hour shifts.
Frequently asked questions
Does adding one month always add the same number of days?
No. Calendar months vary in length. A day-count addition and a calendar-month addition solve different questions.
When is the date to unix timestamp calculator useful?
Convert a civil date at UTC midnight into Unix seconds. Uses UTC midnight, not your local midnight; no time-of-day input is inferred.
How do I use the date to unix timestamp calculator?
Enter utc calendar date. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Unix seconds = milliseconds from epoch to UTC midnight/1000..
What should I check before using the result?
Uses UTC midnight, not your local midnight; no time-of-day input is inferred.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Further reading
For background on this topic, see MDN: date values and calendar handling ↗. This is a topic reference, not an external review or endorsement of this tool.
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