Age Calculator

What the calculator works out

Based on a date of birth and an optional comparison date (today's date by default), the calculator works out the exact age in years, months and days, the total number of days lived between the two dates, and how many days remain until the next birthday.

How the calculation works

Leap years: The calculation accounts for leap years automatically. If someone is born on February 29th, that date counts as a normal birthday in leap years, and the number of days until the next birthday is always based on the actual calendar.

Months of different lengths: Whole months are counted by the calendar months' actual length (28 to 31 days), not as an average. That means the age shown in years, months and days is always exact, regardless of which months fall within the period.

Comparison date: The calculator defaults to today's date as the comparison date, but you can change it to any date, for example to work out an exact age at a specific event or on a document.

Common uses

The age calculator is often used to work out an exact age for applications and forms that require age in years and months, to see how many days remain until a birthday, or to work out someone's age on a specific date in the past or future, such as a graduation day or a wedding.

Limitations

The calculation is based on the Gregorian calendar and works in whole days, it doesn't account for the time of day. If the comparison date falls before the birth date, no result is shown, since an age can't be worked out in that case.