| Document and Entity Information | Jan. 18, 2022 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001637873 |
| Document Type | 8-K |
| Document Period End Date | Jan. 18, 2022 |
| Entity Registrant Name | ACV Auctions Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-40256 |
| Entity Tax Identification Number | 47-2415221 |
| Entity Address, Address Line One | 640 Ellicott Street |
| Entity Address, Address Line Two | #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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Class A common stock, par value $0.001 per share |
| Trading Symbol | ACVA |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
