<PAGE>

                                                                    Exhibit 11.1
                                                                        (1 of 2)

                            Castle Energy Corporation
                 Statement of Computation of Earnings Per Share
                (Dollars in thousands, except per share amounts)
                                   (Unaudited)




<TABLE>
<CAPTION>
                                                                               Year Ended September 30,
                                                         ----------------------------------------------------------------------
                                                                       2000                               1999*
                                                         ------------------------------      ----------------------------------
                                                             Basic            Diluted            Basic             Diluted
                                                         -------------     ------------      ------------       ---------------
<S>                                                      <C>               <C>               <C>                <C>
I.   Shares Outstanding, Net of Treasury
          Stock Purchased and Options Exercised
          During the Period:

          Stock, net                                         7,639,287        7,639,287         8,822,187         8,822,187
          Options exercised (weighted)                                                             19,524            19,524
          Purchase of treasury stock (weighted)               (699,937)        (699,937)         (636,210)         (636,210)
                                                         -------------     ------------      ------------       -----------
                                                             6,939,350        6,939,350         8,205,501         8,205,501

II.   Weighted Equivalent Shares:
          Assumed options and warrants exercised                                163,453                             142,431
                                                         -------------     ------------      ------------       -----------


III. Weighted Average Shares and Equivalent Shares           6,939,350        7,102,803         8,205,501         8,347,932
                                                         =============     ============      ============       ===========

IV.  Net Income                                          $       5,069     $      5,069      $      8,266       $     8,266
                                                         =============     ============      ============       ===========

V.   Net Income Per Share                                $         .73     $        .71      $       1.01       $       .99
                                                         =============     ============      ============       ============
</TABLE>


* Retroactively restated to reflect 200% stock dividend effective January 31,
  2000




<PAGE>



                                                                    Exhibit 11.1
                                                                        (2 of 2)

                            Castle Energy Corporation
                 Statement of Computation of Earnings Per Share
                (Dollars in thousands, except per share amounts)
                                   (Unaudited)











<TABLE>
<CAPTION>
                                                                        Three Months Ended September 30,
                                                         ----------------------------------------------------------------------
                                                                       2000                               1999*
                                                         ------------------------------      ----------------------------------
                                                             Basic            Diluted            Basic             Diluted
                                                         -------------     ------------      ------------       ---------------
<S>                                                      <C>               <C>               <C>                <C>
I.   Shares Outstanding, Net of Treasury
          Stock Purchased and Options Exercised
          During the Period:

          Stock, net                                       6,752,887         6,752,887         7,773,987          7,773,987
          Options exercised (weighted)
          Purchase of treasury stock (weighted)               (2,840)           (2,840)          (49,782)           (49,782)
                                                         -----------       -----------       -----------        -----------
                                                           6,750,047         6,750,047         7,724,205          7,724,205

II.   Weighted Equivalent Shares:
          Assumed options and warrants exercised                               214,594                              122,766
                                                         -----------       -----------       -----------        -----------

III. Weighted Average Shares and Equivalent Shares         6,750,047         6,964,641         7,724,205          7,846,971
                                                           =========       ===========       ===========        ===========

IV.  Net Income                                          $     4,063       $     4,063       $       917        $       917
                                                         ===========       ===========       ===========        ===========

V.   Net Income Per Share                                $       .60       $       .58       $       .12        $       .12
                                                         ===========       ===========       ===========        ===========
</TABLE>

* Retroactively restated to reflect 200% stock dividend effective January 31,
  2000