Age Calculator
How old are you exactly, down to the month and day? This free age calculator works it out from your date of birth in seconds. You can also use it to find the time between any two dates, such as the age difference between two people or how old someone will be on a future date.
How to Use the Age Calculator
- Enter the date of birth (or the earlier date).
- Enter the date you want to calculate the age on. Today's date is often filled in by default.
- Press calculate to see the age in years, months and days.
Depending on the tool settings, you may also see the total age expressed in months, weeks or days, which is useful for babies, pets or milestone celebrations.
How Age Is Calculated
Calculating age is more involved than subtracting years, because months have different lengths and leap years add an extra day. The calculator first counts the complete years between the two dates, then the complete months that remain, and finally the leftover days. This is the same way people naturally describe age: "34 years, 5 months and 12 days".
Doing this by hand is easy to get wrong, especially around the end of a month or across February. An age calculator handles these edge cases consistently, so you get a reliable answer every time.
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Practical Uses for an Age Calculator
- Forms and applications: confirm your exact age for school, visa, insurance or job forms.
- Eligibility checks: see whether you meet a minimum or maximum age on a specific date.
- Birthdays and milestones: find out when you turn 10,000 days old or how long until your next birthday.
- Family and genealogy: work out ages of relatives at historical events.
- Age difference: compare the ages of siblings, partners or colleagues.
Leap Years and February 29 Birthdays
People born on February 29 only see their exact birth date once every four years. In non-leap years, many people celebrate on February 28 or March 1, and legal rules differ by country. The calculator still counts the real time that has passed, so the total days are accurate regardless of how you choose to celebrate.
Related Tools
If you are tracking health goals alongside age, the BMI calculator and calorie calculator both use age-related information in their guidance. For quick arithmetic with dates or numbers, the basic calculator is always available.
Frequently Asked Questions
How do I calculate my exact age?
Enter your date of birth and the date you want to measure to, usually today. The calculator counts complete years, then the remaining months, then the remaining days. The result is your exact age, such as 27 years, 3 months and 9 days, without manual counting.
How many days old am I?
Enter your birth date and today's date, and the calculator can show the total number of days that have passed, depending on the tool's display options. This includes the extra days from leap years, so the total is more accurate than multiplying your age by 365.
How is age calculated for leap-year birthdays (Feb 29)?
The calculator counts the actual time elapsed between the two dates, including leap days. In non-leap years, people born on February 29 often celebrate on February 28 or March 1. Official rules for when a birthday counts legally depend on the country.
Can I calculate the age difference between two people?
Yes. Enter the older person's date of birth as the first date and the younger person's date of birth as the second date. The result is the exact difference between them in years, months and days.
Can I calculate age on a future or past date?
Yes. Instead of today's date, enter any past or future date as the second date. This is useful for checking how old you will be on a deadline, at a future event, or how old someone was on a historical date.