<PAGE>
 
                                                                      EXHIBIT 11
 
VARCO INTERNATIONAL, INC.
STATEMENT RE COMPUTATION OF PER SHARE EARNINGS
 
<TABLE> 
<CAPTION> 
                                                          Three Months   Six Months
                                                            Ended          Ended
                                                         June 30 1997   June 30 1997
                                                         ---------------------------
<S>                                                      <C>            <C>  
A.  CALCULATION OF ADJUSTED EARNINGS

    Net Income After Tax                                  $10,770,000     $18,154,000
</TABLE> 

<TABLE> 
<CAPTION> 
                                                                                         Average                  
                                                                         Total Number     Number     Stock Option   Shares Used 
                                                          Number of    of Shares after  of Shares     Equivalent   To Calculate
                                                             Days         Weighing     Outstanding      Shares         EPS
                                                         --------------------------------------------------------------------------
<S>                                                      <C>         <C>               <C>           <C>          <C>   
B. CALCULATION OF AVERAGE SHARES OUTSTANDING    
 
   Common Stock Outstanding from time-to-time during:
 
    Three Months Ended June 30, 1997                       91         2,888,238,692     31,738,887      839,089     32,577,976
    Six Months Ended June 30, 1997                        181         5,734,623,938     31,683,005      839,089     32,522,094

</TABLE> 

C. CALCULATION OF EARNINGS PER SHARE
 
    Income Per Share =          Net Income After Tax
                             ---------------------------
                              Total Shares Outstanding
 
    Income Per Share =
<TABLE> 
      <S>                                    <C>                             <C> 
      Three Months Ended June 30, 1997          10,770,000         =         $0.33
                                             -------------
                                                32,577,976
 
      Six Months Ended June 30, 1997            18,154,000         =         $0.56
                                             -------------
                                                32,522,094
</TABLE>

<PAGE>
 
                                                                      EXHIBIT 11
 
VARCO INTERNATIONAL, INC.
STATEMENT RE COMPUTATION OF PER SHARE EARNINGS
 
<TABLE> 
<CAPTION> 
                                                         Three Months   Six Months
                                                            Ended          Ended
                                                         June 30 1996   June 30 1996
                                                         ---------------------------
<S>                                                      <C>            <C>  
A.  CALCULATION OF ADJUSTED EARNINGS

    Net Income After Tax                                  $5,679,000     $8,707,000
</TABLE> 

<TABLE> 
<CAPTION> 
                                                                                          Average                  
                                                                         Total Number     Number      Stock Option   Shares Used 
                                                          Number of    of Shares after   of Shares     Equivalent   To Calculate
                                                             Days         Weighing      Outstanding      Shares         EPS
                                                         --------------------------------------------------------------------------
<S>                                                      <C>         <C>               <C>           <C>          <C>   
B. CALCULATION OF AVERAGE SHARES OUTSTANDING    
 
   Common Stock Outstanding from time-to-time during:
 
    Three Months Ended June 30, 1996                       91         2,795,307,505     30,717,665      729,844     31,447,509
    Six Months Ended June 30, 1996                        182         5,542,820,025     30,455,055      729,844     31,184,899
</TABLE> 
 
C. CALCULATION OF EARNINGS PER SHARE
 
    Income Per Share =          Net Income After Tax
                             ---------------------------
                              Total Shares Outstanding
 
 
    Income Per Share =
<TABLE> 
      <S>                                    <C>                             <C> 
      Three Months Ended June 30, 1996           5,679,000         =         $0.18
                                             -------------
                                                31,447,509
 
      Six Months Ended June 30, 1996             8,707,000         =         $0.28
                                             -------------
                                                31,184,899
</TABLE>

                                       2