Age Calculator
Enter a date of birth and a reference date to calculate the exact age in years, months, days, and total days. Useful for personal records, medical forms, and age verification.
How Age Is Calculated
Age is calculated by counting the number of complete years since birth, then the remaining complete months, then the remaining days. The calculation accounts for varying month lengths and leap years automatically.
For example, someone born on March 31 who is calculating their age on May 1 has completed 1 month (March 31 → April 30) plus 1 remaining day (April 30 → May 1). The day count adjusts for the number of days in each month.
FAQ
Does this calculator account for leap years?
Yes. The calculator uses actual calendar dates, so February 29 birthdays are handled correctly. A person born on February 29 technically only has a birthday every 4 years on the exact date; for non-leap years, many jurisdictions legally treat February 28 or March 1 as the birthday. This calculator computes the actual number of days elapsed.
Why does age calculation differ between countries?
In most Western countries, age increases on the birthday — you turn 1 on the first anniversary of your birth. In some East Asian cultures (particularly Korea), age is traditionally calculated differently: everyone is 1 year old at birth and gains a year on January 1. This 'Korean age' can be 1–2 years older than Western age.
Can I calculate the age of something that is not a person?
Yes — this calculator works for anything with a start date: a company's age, the age of a building, how long a project has been running, or any elapsed time from a specific date. Just enter the start date and the 'as of' date.