One often repeated piece of financial advice is to work to minimize your expense ratios in your mutual funds in order to maximize your returns.

While it is often straightforward to determine the expense ratio fee listed on a mutual fund, how can I get an apples to apples comparison between two stock funds to determine the actual ROI (return on investment) and IRR (interest rate of return) of each investment?

Is it as simple as comparing two mutual funds price/share over time? Or does one have to somehow deduct X.XX% off the top?

A numeric example would be helpful here. For the sake of simplicity, lets say the only expenses have to do with expense ratios - for a real world example, lets say I invested $100 into each of 2 index funds, VEIEX and VFIAX, on the following days (values are approximate)

    VEIEX               
     $/share Transaction Type    $ In or Out # shares purchased  IRR
1-Oct-10    28.97   Fixed Buy   ($100)  3.451846738 0.602%
1-Nov-10    30.98   Fixed Buy   ($100)  3.227888961 
1-Dec-10    30.05   Fixed Buy   ($100)  3.327787022 
1-Jan-11    30.34   Sell All     $303.63    -10.00752272    

    VFIAX               
     $/share Transaction Type    $ In or Out # shares purchased  IRR
1-Oct-10    105.53  Fixed Buy   ($100)  0.947597839 2.900%
1-Nov-10    113.03  Fixed Buy   ($100)  0.884720871 
1-Dec-10    113.17  Fixed Buy   ($100)  0.883626403 
1-Jan-11    116.99  Sell All     $317.74    -2.715945113    

Are my IRR calculations accurate? Do i somehow need to take into account the expense ratio for this?

One often repeated piece of financial advice is to work to minimize your expense ratios in your mutual funds in order to maximize your returns.

While it is often straightforward to determine the expense ratio fee listed on a mutual fund, how can I get an apples to apples comparison between two stock funds to determine the actual ROI (return on investment) and IRR (interest rate of return) of each investment?

Is it as simple as comparing two mutual funds price/share over time? Or does one have to somehow deduct X.XX% off the top?

A numeric example would be helpful here. For the sake of simplicity, lets say the only expenses have to do with expense ratios - for a real world example, lets say I invested $100 into each of 2 index funds, VEIEX and VFIAX, on the following days (values are approximate)

VEIEX                 
          $/share   Transaction Type  $ In or Out    # shares purchased  IRR
1-Oct-10    28.97   Fixed Buy         ($100)           3.451846738       0.602%
1-Nov-10    30.98   Fixed Buy         ($100)           3.227888961    
1-Dec-10    30.05   Fixed Buy         ($100)           3.327787022    
1-Jan-11    30.34   Sell All           $303.63       -10.00752272    

VFIAX                 
          $/share   Transaction Type  $ In or Out    # shares purchased  IRR
1-Oct-10   105.53   Fixed Buy         ($100)           0.947597839       2.900%
1-Nov-10   113.03   Fixed Buy         ($100)           0.884720871    
1-Dec-10   113.17   Fixed Buy         ($100)           0.883626403    
1-Jan-11   116.99   Sell All           $317.74        -2.715945113    

Are my IRR calculations accurate? Do i somehow need to take into account the expense ratio for this?