
<PAGE>   1
EXHIBIT 12.1

                          AVALONBAY COMMUNITIES, INC.
   RATIOS OF EARNINGS TO COMBINED FIXED CHARGES AND PREFERRED STOCK DIVIDENDS

<TABLE>
<CAPTION>
                                              Six Months         Year              Year
                                                Ended           Ended             Ended
                                               June 30,       December 31,      December 31,
                                                 2000            1999              1998
                                           ---------------  --------------   ---------------
<S>                                       <C>              <C>              <C>
Net Operating Income                       $       97,829   $     172,276    $      123,535

(Less) Nonrecurring item:
        Gain on sale                       $      (18,752)  $     (47,093)   $      (25,270)
        Non-recurring charges                           -          16,782                 -

(Plus) Extraordinary item:
        Unamortized loan fee write-off     $            -   $           -    $          245

(Plus) Fixed charges:
        Portion of rents representative
                of the interest factor     $          221   $         526    $          293
        Interest expense                           40,430          74,699            54,650
        Interest capitalized                        7,657          21,888            14,724
        Debt cost amortization                      1,328           2,624             2,068
        Preferred dividend                         19,890          39,779            28,132
                                           --------------   -------------    --------------
          Total fixed charges (1)          $       69,526   $     139,516    $       99,867

(Less):
        Interest capitalized               $        7,657   $      21,888    $       14,724
        Preferred dividend                         19,890          39,779            28,132

Adjusted earnings (2)                      $      121,056   $     219,814    $      155,521
                                           --------------   -------------    --------------
Ratio (2 divided by 1)                               1.74            1.58              1.56
                                           ==============   =============    ==============
</TABLE>

<TABLE>
<CAPTION>
                                                 Year             Year             Year
                                                Ended            Ended            Ended
                                             December 31,     December 31,     December 31,
                                                 1997             1996             1995
                                            -------------   ---------------  ---------------
<S>                                        <C>             <C>              <C>
Net Operating Income                        $      64,916   $       51,651   $       30,937

(Less) Nonrecurring item:
        Gain on sale                        $        (677)  $       (7,850)  $            -
        Non-recurring charges                           -                -                -

(Plus) Extraordinary item:
        Unamortized loan fee write-off      $       1,183   $        2,356   $        1,158

(Plus) Fixed charges:
        Portion of rents representative
                of the interest factor      $         172   $          150   $          117
        Interest expense                           16,977            9,545           11,056
        Interest capitalized                        9,024           12,883            6,004
        Debt cost amortization                        700            1,842            1,869
        Preferred dividend                         19,656           10,422                -
                                            -------------   --------------   --------------
          Total fixed charges (1)           $      46,529   $       34,842   $       19,046

(Less):
        Interest capitalized                $       9,024   $       12,883   $        6,004
        Preferred dividend                         19,656           10,422                -

Adjusted earnings (2)                       $      83,271   $       57,694   $       45,137
                                            -------------   --------------   --------------
Ratio (2 divided by 1)                               1.79             1.66             2.37
                                            =============   ==============   ==============
</TABLE>

<PAGE>   2
EXHIBIT 12.1 (CONTINUED)

                          AVALONBAY COMMUNITIES, INC.
                      RATIOS OF EARNINGS TO FIXED CHARGES

<TABLE>
<CAPTION>
                                             Six Months         Year              Year
                                                Ended           Ended             Ended
                                               June 30,      December 31,      December 31,
                                                 2000            1999              1998
                                           ---------------  --------------   ---------------
<S>                                       <C>              <C>              <C>
Net Operating Income                       $        97,829  $       172,276  $      123,535

(Less) Nonrecurring item:
        Gain on sale                       $       (18,752) $       (47,093) $      (25,270)
        Non-recurring charges                            -           16,782               -

(Plus) Extraordinary item:
        Unamortized loan fee write-off     $             -  $             -  $          245

(Plus) Fixed charges:
        Portion of rents representative
                of the interest factor     $           221  $           526  $          293
        Interest expense                            40,430           74,699          54,650
        Interest capitalized                         7,657           21,888          14,724
        Debt cost amortization                       1,328            2,624           2,068
                                           ---------------  ---------------  --------------
          Total fixed charges (1)          $        49,636  $        99,737  $       71,735

(Less):
        Interest capitalized               $         7,657  $        21,888  $       14,724

Adjusted earnings (2)                      $       121,056  $       219,814  $      155,521
                                           ---------------  ---------------  --------------
Ratio (2 divided by 1)                                2.44             2.20            2.17
                                           ===============  ===============  ==============
</TABLE>


<TABLE>
<CAPTION>
                                                Year             Year             Year
                                               Ended            Ended            Ended
                                            December 31,     December 31,     December 31,
                                                1997             1996             1995
                                           -------------   ---------------  ---------------
<S>                                       <C>             <C>              <C>
Net Operating Income                       $      64,916   $       51,651   $       30,937

(Less) Nonrecurring item:
        Gain on sale                       $       (677)   $      (7,850)   $            -
        Non-recurring charges                          -                -                -

(Plus) Extraordinary item:
        Unamortized loan fee write-off     $       1,183   $        2,356   $        1,158

(Plus) Fixed charges:
        Portion of rents representative
                of the interest factor     $         172   $          150   $          117
        Interest expense                          16,977            9,545           11,056
        Interest capitalized                       9,024           12,883            6,004
        Debt cost amortization                       700            1,842            1,869
                                           --------------  --------------   --------------
          Total fixed charges (1)          $      26,873   $       24,420   $       19,046

(Less):
        Interest capitalized               $       9,024   $       12,883   $        6,004

Adjusted earnings (2)                      $      83,271   $       57,694   $       45,137
                                           -------------   --------------   --------------
Ratio (2 divided by 1)                              3.10             2.36             2.37
                                           =============   ==============   ==============
</TABLE>
