Calculadora de Aniversário
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
idade = floor((hoje − nascimento) / 365.25); próximo_aniv = data do aniv no ano corrente ou seguinte
About this calculator
The Birthday Calculator is a practical tool to find out exactly how old you are and how many days are left until your next birthday. Simply enter your date of birth and the calculator does the rest, automatically accounting for leap years. Ideal for planning celebrations or just satisfying curiosity about your precise age.
Age calculation is done by subtracting the birth date from the current date and dividing by 365.25 (to compensate for leap years). Days until the next birthday are calculated by finding the next occurrence of the birthday date, considering whether it has already passed this year. If today is your birthday, the calculator returns zero days remaining.
Use this calculator to plan parties, set reminders, or for legal and medical purposes that require exact age. It is also useful for parents tracking their children's development, or for checking the age of family and friends. Note that the age calculated is the complete age in years, not considering extra months or days.
Caution: the calculator uses your device's time zone, so ensure your system date and time are correct. For people born on February 29, the birthday is considered on February 28 or March 1 in non-leap years, depending on preference; our calculator adopts February 28 as default.
Frequently asked questions
How does the calculator handle leap years?
The calculator uses 365.25 as the divisor for age calculation, which compensates for leap years. For days until the next birthday, it correctly accounts for February having 28 or 29 days.
What if I was born on February 29?
In non-leap years, your birthday is considered on February 28. The calculator adopts this rule for consistency.
Does the calculator consider daylight saving time?
No, it only uses the date, ignoring times. Therefore, daylight saving time does not affect the results.
Can I use the calculator to find someone else's age?
Yes, simply enter that person's date of birth. The calculator will return their current age and days until their next birthday.
Why does the age sometimes seem wrong?
This may happen if your system date is incorrect. Check that your device's date and time are set correctly.