# Calendar.ToFourDigitYear(Int32) Method

## Definition

Converts the specified year to a four-digit year by using the TwoDigitYearMax property to determine the appropriate century.

``````public:
virtual int ToFourDigitYear(int year);``````
``public virtual int ToFourDigitYear (int year);``
``````abstract member ToFourDigitYear : int -> int
override this.ToFourDigitYear : int -> int``````
``Public Overridable Function ToFourDigitYear (year As Integer) As Integer``

#### Parameters

year
Int32

A two-digit or four-digit integer that represents the year to convert.

#### Returns

Int32

An integer that contains the four-digit representation of `year`.

#### Exceptions

`year` is outside the range supported by the calendar.

## Remarks

TwoDigitYearMax is the last year in the 100-year range that can be represented by a two-digit year. The century is determined by finding the sole occurrence of the two-digit `year` within that 100-year range. For example, if TwoDigitYearMax is set to 2029, the 100-year range is from 1930 to 2029. Therefore, a 2-digit value of 30 is interpreted as 1930, while a 2-digit value of 29 is interpreted as 2029.

If `year` is greater than or equal to 100, the value of `year` is returned unchanged.

ToFourDigitYear supports either a two-digit year or a four-digit year. Passing a two-digit year value (less than 100) causes the method to convert the value to a four-digit value according to the TwoDigitYearMax value representing the appropriate century. If the application supplies a four-digit year value that is within the supported calendar range to ToFourDigitYear, the method returns the actual input value. If the application supplies a four-digit value that is outside the supported calendar range, or if it supplies a negative value, the method throws an exception.