Exhibit 12 IRON MOUNTAIN INCORPORATED STATEMENT OF THE CALCULATION OF RATIO OF EARNINGS OF FIXED CHARGES (Dollars in thousands) Pro Forma ------------------------ For the Six Months Year For the Ended Ended Six Months Year Ended December 31, June 30, December Ended ----------------------------------------------- --------------- 31, June 30, 1991 1992 1993 1994 1995 1995 1996 1995 1996 ------- ------ ------ ------ ------ ----- ------ -------- ---------- Earnings: Income (Loss) from Operations before Provision for Income Taxes $(1,292) $ 3,682 $ 3,656 $ 3,241 $ 1,945 $ 1,304 $ 1,585 $ (931) $ (460) Add: Fixed Charges 11,626 11,745 12,125 13,428 16,795 8,339 9,520 24,058 12,347 ------- ------- ------- ------- ------- ------- ------- ------- -------- $10,334 $15,427 $15,781 $16,669 $18,740 $ 9,643 $11,105 $23,127 $11,887 ======= ======= ======= ======= ======== ======= ======= ======= ======== Fixed Charges: Interest Expense $8,612 $ 8,412 $ 8,203 $ 8,954 $ 11,838 $ 5,937 $ 6,385 $17,846 $ 8,921 Interest Portion of Rent Expense 3,014 3,333 3,922 4,474 4,957 2,402 3,135 6,212 3,426 ------- ------- ------- ------- ------- ------- ------- ------- -------- $11,626 $11,745 $12,125 $13,428 $ 16,795 $8,339 $ 9,520 $24,058 $ 12,347 ======= ======= ======= ======= ======== ======= ======= ======= ======== Ratio of Earnings to Fixed Charges 0.9x(1) 1.3x 1.3x 1.2x 1.1x 1.2x 1.2x 0.9x(2) 0.9x(3) ==== ==== ==== ==== ==== ==== ==== ==== ==== (1) The Company reported a pretax loss for the fiscal year ended December 31, 1991. For such period the Company would have needed to generate additional income from continuing operations, before provision for income taxes, of $1,292 to cover its fixed charges of $11,626. (2) On a pro forma basis, the Company would have needed to generate additional income from continuing operations, before provision for income taxes, of $931 to cover its fixed charges of $24,058. (3) On a pro forma basis, the Company would have needed to generate additional income from continuing operations, before provision for income taxes, of $460 to cover its fixed charges of $12,347.