What the Age Calculator does
The Age Calculator computes the time that has elapsed between your date of birth and a chosen reference date. By default, it uses today’s date, but you can set any “as of” date to compare. If you choose to include time, the calculator factors in your time of birth and the reference time to deliver second-level precision.
How to use the Age Calculator
- Enter your date of birth. This is the only required field.
- (Optional) Add your time of birth for precise, time-based results.
- (Optional) Choose an “as of” date and time to calculate your age on a past or future day.
- Check “Include time” if you want the result down to hours, minutes, and seconds.
- Click “Calculate Age” to see your exact age and next birthday details.
What you’ll get
- Exact age in years, months, and days
- Total age in days and weeks
- Expanded totals in hours, minutes, and seconds (when time is included)
- Next birthday date and how many days remain
- Your age on your next birthday
Why precise age matters
Knowing your exact age can be essential for travel, legal documents, competition categories, school enrollment, retirement planning, or personal milestones. A few hours can make a difference when rules or benefits depend on a specific cutoff.
Tips for accurate results
- Use the YYYY-MM-DD format for dates to avoid mistakes.
- If you include time, enter both the time of birth and reference time for the most precise calculation.
- Leaving the reference date/time blank will use your current date/time automatically.
- If you provide a reference date without a time, the calculator assumes midnight (00:00) for that day.
Leap years and special cases
The Age Calculator correctly handles leap years. If you were born on February 29, your next birthday in a non-leap year is treated as February 28 by convention. This ensures the countdown and “next age” remain consistent year to year.
Behind the scenes: how age is calculated
At its core, the Age Calculator measures the interval between your birth moment and the target moment. Without time enabled, it compares whole calendar dates, returning age in years, months, and days, plus total days and weeks. When time is included, it uses exact timestamps to compute hours, minutes, and seconds. This dual approach balances readability (calendar units) with precision (total units).
Common uses of the Age Calculator
- Calculate age for visa, passport, or scholarship applications
- Plan milestone birthdays with accurate countdowns
- Verify eligibility for age-restricted services or events
- Track baby and child growth milestones with precise measurements
Example
Suppose your birth date is 2000-06-15. If today is 2025-10-06, the Age Calculator will show your age in years, months, and days. With time enabled and a known birth time, it will also produce total hours, minutes, and seconds, and tell you exactly how many days remain until your next birthday and how old you’ll be.
Get started
Enter your date of birth, optionally add time, choose an as-of date if needed, and hit Calculate. In seconds, you’ll have a comprehensive breakdown of your age and upcoming birthday information you can use for planning or verification.
