Below code is used to find number of days between two dates

  
    NSDateFormatter *startDateformatter = [[NSDateFormatter alloc]init];
    [startDateformatter setDateFormat:@"dd-MM-yyyy HH:mm:ss"];//setting date formate
    NSDate *startdate = [startDateformatter dateFromString:@"15-01-2011 09:00:00"]; //initializing from date
    NSLog(@"startdate is %@",startdate);
    
    NSDateFormatter *toDateformatter = [[NSDateFormatter alloc]init];
    [toDateformatter setDateFormat:@"dd-MM-yyyy HH:mm:ss"];
    NSDate *toDate = [toDateformatter dateFromString:@"25-01-2011 09:00:00"];//initializing to date
    NSLog(@"toDate  is %@",toDate);
    
    int i = [startdate timeIntervalSince1970];
    int j = [toDate timeIntervalSince1970];
    
    double X = j-i;
    
    int days=(int)((double)X/(3600.0*24.00));
    NSLog(@"Total Days Between::%d",days);