EXHIBIT 11 PLC SYSTEMS INC. CALCULATION OF NET INCOME (LOSS) PER SHARE Three Months Ended March 31, --------- 1997 1996 ---- ---- Weighted average number of common shares outstanding 16,547,000 16,051,000 Common stock equivalents (1) - 979,000 ----------- ---------- Shares used to compute net 16,547,000 17,030,000 income (loss) per share Net income (loss) $(3,022,000) $1,277,000 Net income (loss) per share $(.18) $0.07 (1) The net loss per share is calculated using the weighted average number of shares outstanding during the period and does not include common stock equivalents as their inclusion would be antidilutive.