<PAGE>

                      ERP OPERATING LIMITED PARTNERSHIP
                            CONSOLIDATED HISTORICAL
  EARNINGS TO COMBINED FIXED CHARGES AND PREFERRED DISTRIBUTIONS RATIO

<TABLE>
<CAPTION>
                                                                                         HISTORICAL
                                                            ---------------------------------------------------------------------
                                                                3/31/99          3/31/98           12/31/98         12/31/97     
                                                            ---------------------------------------------------------------------
                                                                                   (Amounts in thousands)
<S>                                                         <C>              <C>              <C>                <C>             
REVENUES

  Rental income                                             $    406,062     $    277,226     $    1,293,560     $    707,733    
  Fee income - outside managed                                     1,234            1,360              5,622            5,697    
  Interest income - investment in mortgage notes                   2,895            4,931             18,564           20,366    
  Interest and other income                                        6,046            2,824             19,703           13,525    
                                                            -------------    -------------    ---------------    -------------   

     Total revenues                                              416,237          286,341          1,337,449          747,321    
                                                            -------------    -------------    ---------------    -------------   

EXPENSES

  Property and maintenance                                        97,047           66,713            326,567          176,075    
  Real estate taxes and insurance                                 42,048           27,443            126,009           69,520    
  Property management                                             14,201           11,579             52,705           26,793    
  Property management -- non-recurring                               -                -                  -                -      
  Fee and asset management                                           867            1,052              4,207            3,364    
  Depreciation                                                    96,901           64,390            301,869          156,644    
  Interest:                                                                                                                      
     Expense incurred                                             79,197           50,254            246,585          121,324    
     Amortization of deferred financing costs                        845              624              2,757            2,523    
  General and administrative                                       5,867            4,880             21,718           15,064    
                                                            -------------    -------------    ---------------    -------------   

     Total expenses                                              336,973          226,935          1,082,417          571,307    
                                                            -------------    -------------    ---------------    -------------   

Income (loss) before extraordinary items                    $     79,264     $     59,406     $      255,032     $    176,014    
                                                            =============    =============    ===============    =============   

Combined Fixed Charges and Preferred Distributions:

   Interest and other financing costs                       $     79,197     $     50,254     $      246,585     $    121,324    
   Amortization of deferred financing costs                          845              624              2,757            2,523    
   Preferred distributions                                        29,377           21,692             92,917           59,012    
                                                            -------------    -------------    ---------------    -------------   

TOTAL COMBINED FIXED CHARGES
   AND PREFERRED DISTRIBUTIONS                              $    109,419     $     72,570     $      342,259     $    182,859    
                                                            =============    =============    ===============    =============   

EARNINGS BEFORE COMBINED FIXED CHARGES
   AND PREFERRED DISTRIBUTIONS                              $    159,306     $    110,284     $      504,374     $    299,861    
                                                            =============    =============    ===============    =============   

FUNDS FROM OPERATIONS BEFORE COMBINED FIXED
   CHARGES AND PREFERRED DISTRIBUTIONS                      $    256,207     $    174,674     $      806,243     $    456,505    
                                                            =============    =============    ===============    =============   

RATIO OF EARNINGS BEFORE COMBINED FIXED CHARGES
    AND PREFERRED DISTRIBUTIONS TO COMBINED FIXED CHARGES
    AND PREFERRED DISTRIBUTIONS                                     1.46             1.52               1.47             1.64    
                                                            =============    =============    ===============    =============   

RATIO OF FUNDS FROM OPERATIONS BEFORE COMBINED FIXED
    CHARGES AND PREFERRED DISTRIBUTIONS TO COMBINED FIXED
    CHARGES AND PREFERRED DISTRIBUTIONS                             2.34             2.41               2.36             2.50    
                                                            =============    =============    ===============    =============   









                      ERP OPERATING LIMITED PARTNERSHIP
                            CONSOLIDATED HISTORICAL
  EARNINGS TO COMBINED FIXED CHARGES AND PREFERRED DISTRIBUTIONS RATIO

                                                                             HISTORICAL
                                                            -------------------------------------------- 
                                                               12/31/96       12/31/95        12/31/94   
                                                            -------------------------------------------- 
                                                                       (Amounts in thousands)
<S>                                                         <C>            <C>             <C>           
REVENUES                                                                                                 
                                                                                                         
  Rental income                                             $    454,412   $    373,919    $    220,727  
  Fee income - outside managed                                     6,749          7,030           4,739  
  Interest income - investment in mortgage notes                  12,819          4,862             -    
  Interest and other income                                        4,405          4,573           5,568  
                                                            -------------  -------------   ------------- 
                                                                                                         
     Total revenues                                              478,385        390,384         231,034  
                                                            -------------  -------------   ------------- 
                                                                                                         
EXPENSES                                                                                                 
                                                                                                         
  Property and maintenance                                       127,172        112,186          66,534  
  Real estate taxes and insurance                                 44,128         37,002          23,028  
  Property management                                             17,512         15,213          10,249  
  Property management -- non-recurring                               -              -               879  
  Fee and asset management                                         3,837          3,887           2,056  
  Depreciation                                                    93,253         72,410          37,273  
  Interest:                                                                                              
     Expense incurred                                             81,351         78,375          37,044  
     Amortization of deferred financing costs                      4,242          3,444           1,930  
  General and administrative                                       9,857          8,129           6,053  
                                                            -------------  -------------   ------------- 
                                                                                                         
     Total expenses                                              381,352        330,646         185,046  
                                                            -------------  -------------   ------------- 
                                                                                                         
Income (loss) before extraordinary items                    $     97,033   $     59,738    $     45,988  
                                                            =============  =============   ============= 
                                                                                                         
Combined Fixed Charges and Preferred Distributions:                                                      
                                                                                                         
   Interest and other financing costs                       $     81,351   $     78,375    $     37,044  
   Amortization of deferred financing costs                        4,242          3,444           1,930  
   Preferred distributions                                        29,015         10,109             -    
                                                            -------------  -------------   ------------- 
                                                                                                         
TOTAL COMBINED FIXED CHARGES                                                                             
   AND PREFERRED DISTRIBUTIONS                              $    114,608   $     91,928    $     38,974  
                                                            =============  =============   ============= 
                                                                                                         
EARNINGS BEFORE COMBINED FIXED CHARGES                                                                   
   AND PREFERRED DISTRIBUTIONS                              $    182,626   $    141,557    $     84,962  
                                                            =============  =============   ============= 
                                                                                                         
FUNDS FROM OPERATIONS BEFORE COMBINED FIXED                                                              
   CHARGES AND PREFERRED DISTRIBUTIONS                      $    275,879   $    213,967    $    123,114  
                                                            =============  =============   ============= 
                                                                                                         
RATIO OF EARNINGS BEFORE COMBINED FIXED CHARGES                                                          
    AND PREFERRED DISTRIBUTIONS TO COMBINED FIXED CHARGES                                                
    AND PREFERRED DISTRIBUTIONS                                     1.59           1.54            2.18  
                                                            =============  =============   ============= 
                                                                                                         
RATIO OF FUNDS FROM OPERATIONS BEFORE COMBINED FIXED                                                     
    CHARGES AND PREFERRED DISTRIBUTIONS TO COMBINED FIXED                                                
    CHARGES AND PREFERRED DISTRIBUTIONS                             2.41           2.33            3.16  
                                                            =============  =============   ============= 
</TABLE>