Exhibit 12 IRON MOUNTAIN INCORPORATED STATEMENT OF THE CALCULATION OF RATIO OF EARNINGS OF FIXED CHARGES (Dollars in thousands) Year Ended December 31, ------------------------------------------------------------------- 1991 1992 1993 1994 1995 ----------- ---------- ---------- ---------- ------------ Earnings: Income (Loss) from Operations before Provision for Income Taxes $(1,292) $ 3,682 $ 3,656 $ 3,241 $ 1,945 Add: Fixed Charges 11,689 12,079 12,430 13,472 17,058 ------- ------- ------- ------- ------- $10,397 $15,761 $16,086 $16,713 $19,003 ======= ======= ======= ======= ======= Fixed Charges: Interest Expense $ 8,612 $ 8,412 $ 8,203 $ 8,954 $11,838 Interest Portion of Rent Expense 3,077 3,667 4,227 4,518 5,220 ------- ------- ------- ------- ------- $11,689 $12,079 $12,430 $13,472 $17,058 ======= ======= ======= ======= ======= Ratio of Earnings to Fixed Charges 0.9x(1) 1.3x 1.3x 1.2x 1.1x ======= ======= ======= ======= ======= Pro Forma ------------------------------- For the For the Six Months Ended Year Six Months June 30, Ended Ended -------------------------------- December 31, June 30, 1995 1996 1995 1996 --------------- -------------- ------------ --------- Earnings: Income (Loss) from Operations before Provision for Income Taxes $1,051 $ 1,585 $(1,576) $ (358) Add: Fixed Charges 8,338 9,520 26,162 13,272 ------ ------- ------- ------ $9,389 $11,105 $24,586 $12,914 ====== ======= ======= ======= Fixed Charges: Interest Expense $5,936 $ 6,385 $19,403 $ 9,699 Interest Portion of Rent Expense 2,402 3,135 6,759 3,573 ------ ------- ------- ------ $8,338 $ 9,520 $26,162 $13,272 ====== ======= ======= ======= Ratio of Earnings to Fixed Charges 1.1x 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 $11,689. (2) On a pro forma basis, the Company would have needed to generate additional income from continuing operations, before provision for income taxes, of $1,576 to cover its fixed charges of $26,162. (3) On a pro forma basis, the Company would have needed to generate additional income from continuing operations, before provision for income taxes, of $358 to cover its fixed charges of $13,272.