Target Age Date Calculator
Add an exact number of calendar years to a birth date to find the corresponding birthday. The result is useful for planning, but legal eligibility can define when an age is attained differently.
Calendar-planning result only, not a legal eligibility decision. Laws and programs can define when an age is attained differently. For a February 29 birth in a non-leap target year, this tool uses March 1 as the planning anniversary and states that convention in the result.
Enter your scenario
Use the details that match your situation. Your estimate stays in this browser.
How this estimate works
- The calculator adds the entered whole number of calendar years to the birth year while preserving month and day.
- For a February 29 birth whose target year is not a leap year, the displayed planning anniversary is March 1 rather than an invalid February date.
- The result is a calendar milestone only; verify the governing rule for voting, pensions, contracts, school, insurance, or other legal uses.
Official calendar and age references
- UK Government Analysis Function: age and date-of-birth harmonised standard
- U.S. Naval Observatory: Gregorian calendar and leap-year rule
The sources explain Gregorian leap years and age/date-of-birth data standards. They do not create a universal legal age-attainment rule.
Frequently asked questions
What happens for a February 29 birthday?
When the target year is not a leap year, this planning calculator displays March 1 and explains the convention. Legal rules can differ.
Can I use this result for legal eligibility?
Use it only as a planning date. Confirm the exact age-attainment rule with the authority responsible for the law or program.