Current and historical p/e ratio for Ciena (CIEN) from 2012 to 2026. The price to earnings ratio is calculated by taking the latest closing price and dividing it by the most recent earnings per share (EPS) number. The PE ratio is a simple way to assess whether a stock is over or under valued and is the most widely used valuation measure.

Please refer to the Stock Price Adjustment Guide for more information on our historical prices.