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DateTimeOffset.AddMonths Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Adds a specified number of months to the current DateTimeOffset object.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public DateTimeOffset AddMonths(
	int months


Type: System.Int32
A number of whole months. The number can be negative or positive.

Return Value

Type: System.DateTimeOffset
An object whose value is the sum of the date and time represented by the current DateTimeOffset object and the number of months represented by months.


The resulting DateTimeOffset value is less than MinValue.


The resulting DateTimeOffset value is greater than MaxValue.

Unlike most of the other methods that add a single time interval unit (such as minutes or days) to a date and time value, AddMonths does not enable you to add fractional parts of a month. To add a time that consists of other time units in addition to months to a DateTimeOffset object, use the Add method.


This method returns a new DateTimeOffset object. It does not modify the value of the current object by adding months to its date and time.

The following example uses the AddMonths method to display the start date of each quarter of the year 2007.

DateTimeOffset quarterDate = new DateTimeOffset(2007, 1, 1, 0, 0, 0,
for (int ctr = 1; ctr <= 4; ctr++)
   outputBlock.Text += String.Format("Quarter {0}: {1:MMMM d}", ctr, quarterDate) + "\n";
   quarterDate = quarterDate.AddMonths(3);
// This example produces the following output:
//       Quarter 1: January 1
//       Quarter 2: April 1
//       Quarter 3: July 1
//       Quarter 4: October 1      

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone