Enter the birth date
Choose the day, month and year of birth. Check the year carefully before reviewing the result.
Other Tools
Age Calculator
Calculate age in years, months and days from a birth date. Choose today or another date to see elapsed days, full weeks and the next birthday.
Your age, broken down
Enter two dates to see years, months and days, plus the next birthday.
- Years
- Months
- Days
- Total days elapsed
- Full weeks + days
Birthday on or after the selected date
Enter a birth date, then select Calculate age.
Dates stay in this page and are not saved or uploaded by this tool. February 29 birthdays use February 28 in non-leap years. Calendar dates only, not exact hours or legal eligibility.
Local processing
Calculate without sharing your birth date
The calculation runs on your device. This tool does not upload or save either date, and no account is needed. Clear removes the current entries; leaving the page also clears them.
Read how BrowserPine handles filesThree simple steps
How to calculate an age
Choose the age-at date
Use today, based on your device’s local date, or select a past or future date on or after the birth date.
Read the age and birthday details
Review calendar years, months and remaining days, total days and weeks, and the birthday countdown from the selected date.
Calendar age and total days are different measures
Calendar months have different lengths. A year-month-day age cannot be converted into total days by treating every month as 30 days or every year as 365 days.
Total days is the difference between the two dates. The birth date starts at zero days elapsed. Full weeks divide that total by seven, with leftover days shown separately.
A consistent rule for leap days and month ends
The calculator counts completed calendar months from the original birth date, then groups each twelve months into one year. For each monthly anniversary it keeps the original day where possible, or uses the last day of that month. Remaining days start from the last completed monthly anniversary.
For example, January 31 to February 28 in a non-leap year is one month. January 31 to March 30 is one month and 30 days: the March anniversary is still March 31. Clamping a short month does not permanently change the birthday to the 28th.
A February 29 birth date uses February 28 as its yearly anniversary in a non-leap year, and February 29 in a leap year. Other calculators and official processes may use different conventions.
Today, a past event or a future date
The age-at date controls every result, including the birthday countdown. If the selected date is an anniversary, the countdown is zero. Otherwise it points to the first anniversary after that date.
Dates use the Gregorian calendar with years 0001 through 9999. The calculation ignores birth times, daylight-saving clock changes and historical switches between calendar systems. It is not an exact-hours calculation or a decision about legal age requirements.
Common questions
Age Calculator FAQ
Can I calculate age on a date other than today?
Yes. Choose any supported age-at date on or after the birth date. The age, elapsed totals and birthday countdown all use that selected date.
How are February 29 birthdays handled?
This calculator uses February 28 as the anniversary in a non-leap year and February 29 in a leap year. It is a stated calculation convention, not a universal rule for official age requirements.
Why can months and days differ between calculators?
Month-end conventions differ. This tool counts months directly from the original birth date, clamping each target monthly anniversary to the last valid day if necessary. It groups twelve completed months into a year and counts remaining days from the last anniversary.
Is the birth date included in total days?
The same birth and age-at date gives zero elapsed days. The following calendar date gives one day. Full weeks contain seven days, with the remainder displayed separately.
Does the calculator include my exact birth time?
No. It compares calendar dates only and does not calculate exact elapsed hours, minutes or seconds.
Is my birth date saved or uploaded?
No. The dates are calculated locally and are not saved or uploaded by this tool. Clear removes the current entries, and leaving the page clears them as well.
What date range can I use?
Use valid Gregorian dates in years 0001–9999, with the age-at date on or after the birth date. If the next birthday falls after year 9999, the age is still shown but that birthday is marked as outside the supported range.
Keep working
Related other tools
Available
Spin the Wheel
Add names or choices and spin to pick one at random. Equal chances per entry, with optional manual list saving in this browser.
View tool
Available
Word & Character Counter
Count words and characters with or without whitespace, and estimate reading time as you type.
View tool