Age in Seconds Calculator
For precise curiosities, scientific timelines, or celebratory milestones—discover age down to the second.
Keep the default to use the current time.
Birth: 1/1/1990, 12:00:00 AM
Reference: 11/25/2025, 11:49:00 AM
Total seconds: 1,132,919,340
Minutes: 18,881,989
Hours: 314,699.82
Days: 13,112.49
Weeks: 1,873.21
Years (approx): 35.900048
How to Use This Calculator
Enter start date/time
Include the precise timestamp for accurate seconds.
Optional: change reference time
Use any historical or future moment to compare.
Review the conversions
Get seconds plus minute, hour, day, and year equivalents.
Formula
Seconds = (Reference − Birth) ÷ 1,000
Minutes = Seconds ÷ 60 • Hours = Seconds ÷ 3,600
Days = Seconds ÷ 86,400 • Years ≈ Seconds ÷ 31,557,600
Example: 1990-01-01 → 2025-11-09 ≈ 1,136,197,200 seconds → 31,561 days.
Second-Based Use Cases
- Celebrate milestones (e.g., 1 million seconds together).
- Align timestamps in data science, IoT, or logging systems.
- Convert wait times or SLAs into precise seconds.
- Teach kids the scale between seconds and years.
Frequently Asked Questions
Does the calculator include leap seconds?
Standard JavaScript dates ignore leap seconds. Results match civil timekeeping used by most systems.
What if precision below seconds is needed?
Currently we round to the nearest second. For sub-second analysis, consider using specialized timing tools.
Can I use this for multiple events?
Yes—repeat the calculation for each event pair you want to compare.
Why is there an “approximate years” value?
Years vary because of leap years; we use the common average of 365.25 days for quick conversions.