Age Calculator
Calculate exact age in years, months, and days from a date of birth. Shows total days lived and days until next birthday.
Your Age
35 years 10 months 4 days
Total Days
13,092
Total Weeks
1,870
Total Months
430
Next Birthday
57d to go
How to use this calculator
- Click the date field and select your date of birth.
- Your exact age appears instantly in years, months, and days.
- Scroll down to see total days lived, total weeks, and how many days until your next birthday.
How Age Is Calculated: Beyond Just Counting Years
Legal, medical, and administrative contexts often need exact age in years and months — not just whole years. This tool decomposes the interval into years, remaining months, and remaining days.
The approach matches SQL DATEDIFF / Excel DATEDIF: full years, then full months, then days — respecting varying month lengths and leap years.
Total days lived and countdown to the next birthday are useful for planning and milestones. This calculator handles edge cases like Jan 31 → Feb correctly.
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Frequently Asked Questions
How is the exact age calculated?
The calculator subtracts your birth date from today's date using calendar arithmetic. Years are counted first, then the remaining months, then the remaining days — matching how age is officially recorded on documents.
Why does my age show in years, months and days?
Most people only know their age in whole years, but breaking it down into months and days gives you a more precise answer — useful for legal forms, medical records, or just satisfying curiosity.
How is 'total days lived' calculated?
Every calendar day from your birth date up to and including today is counted, including leap-year extra days. The result is the exact number of days you have been alive.
What is the 'days until next birthday' count?
The tool finds the next occurrence of your birth month and day (in the current or next year) and counts the days from today to that date. If today is your birthday, it returns 0.
Does this work for any birth date?
Yes, any past date is supported. Dates very far in the past may differ slightly from historical calendars because the tool uses the proleptic Gregorian calendar throughout.
What is the 10,000 days milestone?
Reaching 10,000 days alive (roughly 27 years and 4–5 months) is a popular personal milestone. The tool highlights it in the output so you can see whether you have passed it yet.
How does age calculation handle leap year birthdays (Feb 29)?
When your birthday falls on Feb 29 and the current year is not a leap year, the calculator treats March 1 as your birthday for the purposes of counting age and days until next birthday.