8. Earnings Per Share

3 Months Ended

Mar. 31, 2020

. EARNINGS PER SHARE

Basic earnings per share is computed by dividing net income attributable to Bio-Rad by the weighted average number of common shares outstanding for that period. Diluted earnings per share takes into account the effect of dilutive instruments, such as stock options and restricted stock, and uses the average share price for the period in determining the number of potential common shares that are to be added to the weighted average number of shares outstanding. Potential common shares are excluded from the diluted earnings per share calculation if the effect of including such securities would be anti-dilutive.

The weighted average number of common shares outstanding used to calculate basic and diluted earnings per share, and the anti-dilutive shares that are excluded from the diluted earnings per share calculation are as follows (in thousands):



	Three Months Ended
	March 31,
	2020	2019
Basic weighted average shares outstanding	29,865	29,801
Effect of potentially dilutive stock options and restricted stock awards	331	303
Diluted weighted average common shares	30,196	30,104
Anti-dilutive shares	62	226