Cover Page - shares	6 Months Ended
	Sep. 30, 2021	Nov. 12, 2021
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-13007
Entity Registrant Name	CARVER BANCORP, INC.
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	75 West 125th Street
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Tax Identification Number	13-3904174
Entity Address, Postal Zip Code	10027
City Area Code	(718)
Local Phone Number	230-2900
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Smaller Reporting Company	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		3,500,200