Age Calculator — Find Your Exact Age in Years, Months & Days
Calculate exact age in years, months, days
Enter your date of birth to get your exact age. Also shows days until your next birthday and what day of the week you were born.
About Age Calculator
An age calculator determines your exact age in years, months, and days from your date of birth to a given reference date — typically today. While simple subtraction gives approximate age in years, precise calculation requires accounting for leap years, varying month lengths, and the specific day of the month.
Beyond basic age calculation, this tool provides additional contextual information: the total number of days you have been alive, the day of the week on which you were born, and the number of days remaining until your next birthday. These details are useful for personal milestones, official documentation, and simple curiosity.
Exact age calculation matters in legal, medical, and administrative contexts. Age eligibility thresholds — for voting, retirement, driving licences, school enrolment, medical screening programmes, and age-restricted services — require precision to the day in many jurisdictions.
The tool performs all date arithmetic using JavaScript's built-in Date API, which correctly handles leap years and month-length variations. Calculations are instantaneous and performed entirely in your browser. No date of birth data is stored, transmitted, or logged. The tool is equally useful for calculating the age of companies, events, or any dated entity — simply enter the founding or start date as the "date of birth".
Frequently Asked Questions
How is the exact age calculated?
The tool calculates the difference between your date of birth and today (or a target date you specify) in complete years, remaining months, and remaining days — accounting for leap years and varying month lengths.
Can I calculate the age at a specific past or future date?
Yes. The tool defaults to today but you can enter any reference date to calculate age at that point in time.
Why does "days until next birthday" vary each year?
Leap years add an extra day, and the number of days between your birthday and the current date changes each year depending on how many months have elapsed.
On which day of the week was I born?
Enter your date of birth and the tool will display the weekday. This is calculated using the Zeller's congruence algorithm or equivalent date arithmetic.