Age to Birthday Calculator
Convert between age and birthday date with custom reference dates
Age to Birthday Converter
The date on which the age calculation is based
Enter the age to calculate birthday
Select the unit for age calculation
⚠️ Reference date is required
Example Calculations
Age to Birthday Examples
If someone is 25 years old on Invalid Date:
Their birthday is September 4, 2000
If someone is 18 years old on Invalid Date:
Their birthday is September 4, 2007
If someone is 30 years old on Invalid Date:
Their birthday is September 4, 1995
Calculation Modes
Common Use Cases
Document verification
School enrollment
Employment verification
Medical records
Genealogy research
Quick Facts
Bidirectional conversion between age and birthday
Custom reference date support
Supports years, months, and days
Accurate leap year calculations
Understanding Age to Birthday Conversion
How the Calculator Works
This bidirectional calculator converts between age and birthday using a reference date. It can calculate your birthday from your age or determine your age from your birthday.
Age to Birthday Mode
- •Enter your age and select the unit (years, months, days)
- •Set a reference date (when you have that age)
- •Calculator determines your birth date
Birthday to Age Mode
- •Enter your birth date
- •Set a reference date (when to calculate age)
- •Calculator determines your exact age
Applications
- Legal: Document verification and validation
- Educational: School enrollment age requirements
- Medical: Patient age verification
- Research: Historical and genealogical studies
Note: The reference date determines when the age calculation is valid.