Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 03, 2022
Document Information [Line Items]
Entity Registrant Name	ACV Auctions Inc.
Entity Central Index Key	0001637873
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Document Type	10-Q
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Trading Symbol	ACVA
Amendment Flag	false
Title of 12(b) Security	Class A common stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Entity File Number	001-40256
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-2415221
Entity Address, Address Line One	640 Ellicott Street, #321
Entity Address, City or Town	Buffalo
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	14203
City Area Code	800
Local Phone Number	553-4070
Document Quarterly Report	true
Document Transition Report	false
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		115,198,004
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		42,482,431