EXHIBIT 12.1

Corporate Office Properties Trust

Ratio of Earnings to Combined Fixed Charges and Preferred Share Dividends

(Dollars in thousands)

		Years Ended December 31,
		2017				2016				2015				2014				2013
Earnings:
Income (loss) before equity in income of unconsolidated entities and income taxes		$	64,659			$	(26,419	)		$	120,812			$	34,590			$	36,704
Gain on sales of real estate		9,890				40,986				68,047				10,671				9,016
Combined fixed charges and preferred share dividends (from below)		89,737				104,541				111,737				115,842				120,307
Amortization of capitalized interest		2,631				2,715				2,591				2,374				1,977
Distributed income of equity investees		1,496				732				361				225				1,857
Subtract:
Capitalized interest (from below)		(5,229		)		(5,723		)		(7,151		)		(6,065		)		(8,785		)
Preferred share dividends included in fixed charges		(6,219		)		(14,297		)		(14,210		)		(15,939		)		(19,971		)
Preferred unit distributions included in fixed charges		(660		)		(660		)		(660		)		(660		)		(660		)
Preferred distributions of other consolidated entities		(16		)		(16		)		(16		)		(16		)		(16		)
Total earnings		$	156,289			$	101,859			$	281,511			$	141,022			$	140,429
Combined Fixed Charges and Preferred Share Dividends:
Combined fixed charges and preferred share dividends:
Interest expense on continuing operations		$	76,983			$	83,163			$	89,074			$	92,393			$	82,010
Interest expense on discontinued operations		—				—				—				—				8,221
Capitalized interest (internal and external)		5,229				5,723				7,151				6,065				8,785
Amortization of debt issuance costs-capitalized		—				—				8				186				144
Interest included in rental expense		630				682				618				583				500
Preferred share dividends		6,219				14,297				14,210				15,939				19,971
Preferred unit distributions		660				660				660				660				660
Preferred distributions of other consolidated entities		16				16				16				16				16
Total combined fixed charges and preferred share dividends		$	89,737			$	104,541			$	111,737			$	115,842			$	120,307
Ratio of earnings to combined fixed charges and preferred share dividends		1.74				0.97				2.52				1.22				1.17
Deficiency						$	2,682

For purposes of calculating the above ratios, earnings were computed by adding fixed charges (excluding capitalized interest), gain on sales of real estate (excluding discontinued operations), amortization of capitalized interest and distributed income of equity investees to income before noncontrolling interests, equity in income of unconsolidated entities and income taxes. Fixed charges consist of interest costs and capitalized amortization of debt issuance costs.