Age Calculator
Enter a date of birth and a reference date to find the age in completed years, plus years, months and days, the next birthday and the days until it.
How age is counted
Age here means completed years: it goes up by 1 each time a birthday arrives. This calculator shows the new age from the birthday itself.
- A person born on April 1, 2000 is 26 on October 24, 2026. The next birthday is April 1, 2027, when they turn 27.
- "Years, months and days" is the time from the most recent birthday to the reference date, counted in months and days. If the month you land in does not have that day, the last day of that month is used (the same approach as the days between dates calculator).
- "Days since birth" is the reference date minus the date of birth; the day of birth is day 0.
People born on February 29
February 29 exists only in leap years. In years that are not leap years, this calculator counts the new age from March 1. In leap years, the new age starts on February 29.
For someone born on February 29, 2000, the age changes on March 1, 2027 (not a leap year) and on February 29, 2028 (a leap year). This is the rule used by this calculator. Other places, organizations and purposes may count the birthday of a leap-day birth on February 28 or on March 1, so check the rule that applies to you when it matters.
Notes
- Dates can be entered from January 1, 1900 to December 31, 2100. If the reference date is before the date of birth, an error is shown.
- If your browser shows a text box instead of a date picker, enter dates as YYYY-MM-DD (for example 2026-10-24). Dates such as 03/04/2026 are not accepted, because they can mean March 4 or April 3.
- Other ways of counting age, such as the traditional East Asian systems, and school-year cutoffs are not covered.
Frequently asked questions
How do I calculate age from a date of birth?
Enter the date of birth and the reference date. The age is the number of birthdays that have passed up to the reference date.
How do I get my age today?
Press "Use today's date" under the reference date. It fills in the date on your device.
When does a leap-day birthday count as a new year of age?
In this calculator, on March 1 in years that are not leap years, and on February 29 in leap years.