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Total days lived
Exact Age Calculator in Years, Months & Days
Official forms, eligibility checks and milestone planning often need more than “about 30.” This age calculator subtracts a birth date from today (or any second date you choose) and returns the precise difference in years, months and days. It also shows total days lived and how many days remain until the next birthday.
Please enter a valid date of birth that is not after the target date.
Your age is
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Total months
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Days to next birthday
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Born on a
How to Use the Age Calculator
- Enter the date of birth.
- Optionally change the “as of” date if you need age on a past or future day.
- Calculate to see years, months, days and total days.
- Note the next-birthday countdown for planning.
Pick your date of birth. Leave “Calculate age on” empty to use today’s date, or choose another day to find your age on a past or future date. The date of birth cannot be after that day. The result shows your age in years, months and days, plus total days lived, total months, days to your next birthday and the weekday you were born.
Age Calculator Formula Explained
Calendar Date Difference with Month-Length Handling
Years, months and days are computed by subtracting calendar components and borrowing when the day or month underflows. Leap years are respected when counting February days. Total days is a simple serial-day difference. The algorithm avoids treating every month as 30 days.
The calculator counts whole calendar months from the birth date, then counts the remaining days. If the birth day does not exist in a month, such as 31 in a 30-day month, it uses that month’s last day. Total days is the exact number of days between the two dates. For a 29 February birthday, the next birthday is counted as 28 February in years that are not leap years.
Age Calculator Example Calculation
If someone was born on 15 March 1995 and you check their age on 15 March 2026, the result is exactly 31 years, 0 months and 0 days. Shifting the as-of date by a few days changes the months and days components while the year count updates only after the birthday passes. This precision matters for forms, sports age groups and eligibility checks.
Worked example: date of birth 15 March 1995, with “Calculate age on” set to 3 October 2026. The calculator shows 31 years, 6 months and 18 days. Total days lived is 11,525, total months is 378, and days to the next birthday is 163. The weekday of birth is Wednesday. With 15 March 2026 as the “age on” date, the result is exactly 31 years, 0 months and 0 days.
When to use this tool
Use this tool when official forms ask for exact age rather than year of birth alone, when you need days lived for personal records, or when planning a milestone birthday. It avoids manual calendar errors around month lengths and leap years.
Key Features & Benefits of This Age Calculator
- Years, months and days — plus total days lived and total months.
- Any “as of” date — leave it empty to use today, or pick a past or future date to find your age on that day.
- Birthday countdown and birth weekday — see the days to your next birthday and the weekday you were born.
- Leap years handled — real month lengths are used, and a 29 February birthday is counted as 28 February in years that are not leap years.
- Instant, free and private — runs entirely in your browser, no sign-up, nothing stored.
Good to know
Official forms often require age in years, months and days rather than a simple year count. Running the calculation with the correct as-of date reduces rejection risk on applications for benefits, licences and education programmes.
Age Calculator — FAQs
Does the calculator handle leap years?
Yes. February 29 is counted correctly in leap years and adjusted when the target year is not a leap year.
Can I calculate age on a future date?
Yes. Set the “as of” date to any future day to see age on that date.
Why do some online tools disagree by a day?
Time-zone boundaries and whether the birth day itself is counted can create one-day differences. This tool uses date-only arithmetic in local interpretation.
Does the calculator account for leap years?
Yes — it counts actual days between the two dates including every leap day, so the years/months/days breakdown is exact rather than approximate.