Basic and diluted earnings (loss) per share (Tables)

12 Months Ended

Dec. 31, 2020

Basic and diluted earnings (loss) per share

Schedule of diluted net income and potentially dilutive shares utilized in the per share calculation

Basic	2020		2019
Numerator:
Net income (loss) attributable to Atlantic Power Corporation	$	74.2	$	(42.6)
Denominator:
Weighted average basic shares outstanding		95.8		109.3
Basic earnings (loss) per share attributable to Atlantic Power Corporation	$	0.77	$	(0.39)
Diluted
Numerator:
Net income (loss) attributable to Atlantic Power Corporation		74.2		(42.6)
Add: convertible debenture interest expense		3.8		—
		78.0		(42.6)
Denominator:
Weighted average basic shares outstanding		95.8		109.3
Share-based compensation		1.7		—
Convertible debentures		27.4		—
		124.9		109.3
Diluted earnings (loss) per share attributable to Atlantic Power Corporation		0.62		(0.39)

Summary of outstanding instruments that are anti-dilutive and not included in the computation of our diluted (loss) earnings per share

	2020		2019
Share-based compensation		—		1.5
Convertible debentures		—		27.8
Total		—		29.3