What this calculator does
Exact age is the calendar difference between your date of birth and a reference date, expressed in years, months and days. Legal age thresholds depend on whether the birthday has passed.
This calculator also shows total days and weeks, approximate hours and the time until your next birthday. Change the reference date to calculate age at any point.
Age calculation
Age = year difference + month correction + day correction If the birthday has not yet occurred, one year is subtracted. Month and day differences are corrected using calendar month lengths.
How this calculator works
- 01
Choose a birth date
Enter the day, month and year of birth.
- 02
Set a reference date
Today is the default; any past or future date works.
- 03
Read the details
See years, months, days, total days and the countdown to your next birthday.
Frequently asked questions
Why does the birthday matter for legal age?
A year of life is complete only when the birthday is reached. Legal age thresholds therefore depend on the exact date, not just the birth year.
Why do month and day totals differ?
Months have 28–31 days and leap years add a day. Calendar-based calculation accounts for those differences.
Can I calculate age at a future date?
Yes. Set the reference date to any future day and the calculator shows the age at that point.
Data basis: 2026 · Annual constants live in structured JSON files and are updated once a year.
Results are unverified model calculations and do not replace tax, legal or financial advice.