Create a new class with name CookieHelper.cs In your project and paste the following code. public class CookieHelper { #region Constants /// <summary> /// The cookie name /// </summary> public const string cookieName = "UserName"; #endregion #region Enums public enum EnumCookieInterval { SECOND = 0, MINUTE = 1, DAY = 2, MONTH = 3, YEAR = 4 }; #endregion #region Utilities /// <summary> /// Calculates the cookie lifetime. /// </summary> /// <param name="duration">The duration.</param> /// <param name="durationType">Type of the duration.Use enum to specify</param> /// <returns>Expire date for cookie</returns> private static DateTime CalculateCookieLifetime(int duration, Enum