Age Difference Calculator
Perfect for siblings, partners, or friends—find exactly how far apart two people are in age as of any reference date.
Use today or another date of interest.
Age Comparison
Person A
33 year(s), 5 month(s), 24 day(s)
≈ 12,230 days old
Person B
30 year(s), 9 month(s), 10 day(s)
≈ 11,241 days old
How to Use This Calculator
Enter both birth dates
Use ISO dates for quick accuracy. The calculator handles any order and determines who is older automatically.
Set a reference date
Choose today or the date you want to compare ages on (e.g., a wedding day or graduation).
Review the age gap
See each person’s age on the reference date, plus the precise difference expressed in years, months, days, and total days.
Formula
Age Person = Reference − Birth (calendar difference)
Difference = Younger Birth − Older Birth
Total Days = floor(Difference ÷ 86,400,000 ms)
Example: 1992-06-01 vs 1995-02-15 → Age gap is 2 years, 8 months, 14 days (989 days).
Why Track Age Differences?
Knowing the exact age gap helps with school enrollment timing, sibling milestones, relationship anniversaries, and navigating legal age thresholds.
- Plan joint celebrations by understanding who reaches milestones first.
- Confirm eligibility where age gaps matter (sports leagues, adoption paperwork, etc.).
- Use the total days for fun trivia or social media captions.
- Track family genealogy with precise age comparisons across generations.
Frequently Asked Questions
Does birth order matter?
The tool automatically determines who is older and labels them accordingly.
Can I compare more than two people?
Compare two at a time, or run multiple calculations. For groups, consider creating a table using this calculator iteratively.
How precise is the days count?
It’s exact—computed using the difference in UTC timestamps, accounting for leap years.
What about time zones?
Birth time zones don’t affect the result as long as dates are correct. If exact birth times matter, convert to UTC first.