FREE ONLINE AGE TOOL
Age Calculator
Calculate your exact age in years, months and days, along with total months, weeks, days and your next birthday countdown.
How to Use the Age Calculator
- Enter your date of birth in the Date of Birth field.
- Keep today’s date selected in Calculate Age On, or choose another date to find your age on that specific day.
- Click the Calculate Age button.
- Review your exact age in years, months and days.
- You can also see your total months, weeks, days and the number of days remaining until your next birthday.
- Want to see exactly how much time is left until your next birthday? Use our Birthday Countdown Calculator to check the remaining months, days, hours, minutes and seconds.
How Is Your Age Calculated?
The calculator counts complete calendar months between Date of Birth and Calculate Age On, splits those months into years and months, and counts remaining calendar days. If a month anniversary exceeds that month’s final day, it uses the last valid day. This is a calendar age rather than an elapsed-hours calculation.
Enter January 15, 2000 as Date of Birth and April 27, 2025 as Calculate Age On. The result is 25 years, 3 months and 12 days: January 15, 2025 completes 25 years, April 15 adds three months, and April 27 adds 12 days. Total Months is 303, Total Days is 9,234 and Total Weeks is 1,319, with one day outside the complete weeks.
The Total Days result shows the complete number of calendar days between the two selected dates. Total Weeks are calculated from the number of completed seven-day periods.
Total Months means complete calendar months. Total Weeks means completed seven-day periods; neither is a rounded decimal age.
Month-End and February 29 Examples
January 31, 2025 to February 28, 2025 gives 0 years, 1 month and 0 days, although only 28 calendar days have passed. February 28 is the adjusted monthly anniversary.
For a birth date of February 29, 2000, February 28, 2027 gives 27 years, 0 months and 0 days, and Next Birthday shows Today. February 28, 2028 gives 27 years, 11 months and 30 days, with 1 day until the birthday; February 29, 2028 gives exactly 28 years.
Age Calculation Limits
Calculate Age On may be in the past or future but cannot precede the birth date. Next Birthday is measured from that selected calculation date, so changing the date also changes the birthday result.
The tool uses Gregorian dates and does not ask for a birth time or time zone. This version supports years 0100 to 9999. Its February 28 convention does not choose your celebration date or establish an official age-eligibility rule.
Frequently Asked Questions
How accurate is this Age Calculator?
The calculator uses calendar dates to calculate completed years, months and days. It also accounts for different month lengths and leap years.
Can I calculate my age on a past or future date?
Yes. Change the Calculate Age On field to any valid date that is not earlier than your date of birth.
Why is total weeks shown as a whole number?
Total Weeks represents the number of complete seven-day periods between your date of birth and the selected calculation date.
How are leap-year birthdays handled?
For a February 29 birth date, the tool uses February 28 as the anniversary in a non-leap year and February 29 in a leap year. Someone born on February 29, 2000 reaches a displayed age of 27 on February 28, 2027 and 28 on February 29, 2028.
Does this website save my date of birth?
The calculator’s own code performs the calculation locally in your browser and does not submit the entered dates to a server. For site cookies and any analytics, read our Privacy Policy.
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