QuickLinks -- Click here to rapidly navigate through this document

Exhibit 12.1


Antero Resources LLC
Ratio of Earnings to Fixed Charges
(in thousands, except ratio)

 
  2005   2006   2007   2008   2009   Pro forma
2009
  Three Months
Ended March 31,
2010
 

Earnings:

                                           

Net income (loss) before income taxes

    (46,634 )   (8,583 )   (38,153 )   86,709     (109,137 )   (109,137 )   100,164  

Interest expense

    592     1,366     25,124     37,594     36,089     36,089     13,292  

Interest component of rental expense

    69     67     99     175     295     295     67  
                               
   

Earnings

    (45,973 )   (7,150 )   (12,930 )   124,478     (72,753 )   (72,753 )   113,523  
                               

Fixed charges:

                                           
 

Interest expense

    592     1,366     25,124     37,594     36,089     36,089     13,292  
 

Interest component of rental expense

    69     67     99     175     295     295     67  

Pro forma adjustments:

                                           
 

Incremental interest expense on issuance of notes

                                  20,161        
                               
   

Fixed charges

    661     1,433     25,223     37,769     36,384     56,545     13,359  
                               

Ratio of earnings to fixed charges

    NA     NA     NA     3.30     NA     NA     8.50  



QuickLinks

Antero Resources LLC Ratio of Earnings to Fixed Charges (in thousands, except ratio)