Age Calculator
Calculate completed age from a birth date to today or a selected reference date.
Age Calculator
Find age between a birth date and an explicit reference date.
Instructions:
- Enter your date of birth
- Choose the date on which you want to measure the age
- Results use calendar dates, not time of day
Explore More Time Tools
Continue with related pages to compare results and improve decision making.
How This Age Calculator Works
This age calculator finds completed calendar years, months, days, and total elapsed days between a birth date and either today or a reference date you choose.
Formula and Calculation
The core formula used by this age calculator is: Age is the completed calendar difference between the selected reference date and date of birth, split into years, months, and days.
The calculator counts complete years first, then remaining months and days, using constrained calendar arithmetic when an anniversary day does not exist in a target month.
For an application with a fixed eligibility date, select that date as the reference date and compare the result with the institution’s stated age and date-counting rules.
How to Use This Calculator
- Enter your date of birth.
- Choose reference date if different from today.
- Run the calculation to view completed calendar age.
- For eligibility or official records, verify the institution’s date-counting rules before relying on the result.
Why Use This Age Calculator?
- Get completed calendar age without manual date math.
- Avoid errors around birthdays and leap years.
- Calculate age as of today or another date.
- Supports planning for milestones and eligibility.
Related Tools and Guides
- Try the Date Difference Calculator for a related calculation.
- Try the Time Duration Calculator for a related calculation.
- Read the Age Calculator Guide for examples and assumptions.
- Browse the Time Calculators page for more tools.