Calculating how many minutes there are between two times
double minutes = varTime.TotalMinutes;
int minutesRounded = (int)Math.Round(varTime.TotalMinutes);
TimeSpan.TotalMinutes: The total number of minutes represented by this instance.
Try this
DateTime startTime = varValue
DateTime endTime = varTime
TimeSpan span = endTime.Subtract ( startTime );
Console.WriteLine( "Time Difference (minutes): " + span.TotalMinutes );
Edit: If are you trying 'span.Minutes', this will return only the minutes of timespan [0~59], to return sum of all minutes from this interval, just use 'span.TotalMinutes'.