1 EXHIBIT 12 NAPCO SECURITY SYSTEMS, INC. AND SUBSIDIARIES COMPUTATION OF RATIOS 1999 1998 1997 ---- ---- ---- (In thousands, except for ratios) A. Current Assets $41,696 $44,153 $42,021 B. Current Liabilities 6,776 10,211 11,885 Current Ratio (Line A / Line B) 6.2 to 1 4.3 to 1 3.5 to 1 C. Sales $50,573 $50,269 $53,302 D. Receivables 16,446 14,760 13,937 Ratio (Line C / Line D) 3.1 to 1 3.4 to 1 3.8 to 1 E. Total Current Liabilities $6,776 $10,211 $11,885 F. Long Term Debt 17,241 18,644 13,313 G. Deferred Income Taxes 442 875 828 H. Total Liabilities 24,459 29,730 26,026 I. Equity 31,328 28,833 31,218 Ratio (Line H / Line I) .8 to 1 1.0 to 1 .8 to 1 E-34