Age calculator
Enter a date of birth and get the exact age in years, months, and days, the days lived, and how long is left until the next birthday.
Enter your date of birth to calculate your exact age.
Happy birthday!
Age difference
How it is calculated
- Formula
—- With your values
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Your age goes up on your birthday. If you were born on February 29, in non-leap years February 28 or March 1 is used, depending on what you choose in “More options”.
How to use it
- Enter the date of birth as mm/dd/yyyy, or pick it from the calendar.
- By default the age is calculated for today. If you need the age on another day, change “Calculate age on”, for example for an application or a form.
- Read the age in years, months, and days, and the totals in months, weeks, days, and hours.
- See when the next birthday is, which day of the week it falls on, and how many days are left. Turn on “Compare with another person” to see who is older and by how much.
Frequently asked questions
How is the exact age calculated?
The calculator counts the completed years, then the full months since the last birthday, and finally the leftover days. Your age goes up on the day of your birthday, not before.
What if I was born on February 29?
In years that are not leap years, the calculator treats February 28 as your birthday by default. Some legal rules use March 1: in “More options” you can choose that rule and see how the result changes.
Can I calculate the age on a past or future date?
Yes. Change “Calculate age on” and you will see the age you were or will be on that day. The date cannot be earlier than the date of birth.
How many days have I lived?
The total number of days appears under the age, along with the months, weeks, and hours. Hours are calculated as full days times 24.
Is the zodiac sign exact?
It uses the usual date ranges for each sign. The cutoff between signs can shift by a day from year to year, so if you were born right on the edge, double-check it with a birth chart.
Is my date of birth saved?
No. The calculation happens in your browser. This tool does not save the date or include it in the page link.
Age in years, months, and days
Exact age is not just the difference between birth years. It depends on whether this year’s birthday has already passed. A person born on March 15, 1990 is, on September 29, 2026, 36 years, 6 months, and 14 days old.
When you need an exact age
- Forms and requirements: legal adulthood, retirement benefits, school enrollment cutoffs, or age limits for contests and sports leagues.
- Health: babies’ ages are tracked in months and weeks, not years.
- Curiosity: how many days, weeks, or hours you have been alive.
Born on February 29
February 29 only exists in leap years. In other years, this calculator uses February 28 as your birthday by default, and in “More options” you can choose March 1. Each legal rule can set its own criterion, so check the one that applies to your case.
Calculating the age on another date
Changing the calculation date is useful to find out how old you will be when a school year starts, or how old you were when something happened. Just pick the day you are interested in. For other health-related numbers, the BMI calculator in kilograms and centimeters works out your body mass index.
Updated on September 29, 2026