Age Calculator
Find your exact age in years, months and days, plus a countdown to your next birthday.
Age Calculator
Find your exact age in years, months and days, plus a countdown to your next birthday.
How to use the Age Calculator
- Enter your date of birth.
- Optionally enter an "age at date" to calculate age as of a specific day (defaults to today).
- Click Calculate.
Formula
Calendar-based year, month, day subtraction accounting for varying month lengths.
Example
Born March 15, 1990; today August 21, 2026: 36 years, 5 months, 6 days.
Step-by-step calculation
- Compare month and day of birthday vs. target date.
- If target month/day is before birthday, subtract 1 year.
- Calculate remaining months and days using calendar month lengths.
- Result: 36 years, 5 months, 6 days.
Real-world uses
- Verifying age requirements.
- Birthday and anniversary planning.
- Insurance and eligibility checks.
Common mistakes
- Assuming every year is 365 days (leap years affect the calculation).
- Entering the date in the wrong format.
- Forgetting that age changes on your birthday, not on New Year's Day.
Frequently asked questions
Does this account for leap years?
Yes. The calculator uses actual calendar dates, so leap years are handled correctly.
Can I calculate age in days only?
The tool shows years/months/days breakdown plus total days, weeks, and months.
What if the birthday hasn't occurred yet this year?
The calculator handles this correctly by comparing month and day, not just year subtraction.