| Document And Entity Information | Feb. 22, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Feb. 22, 2022 |
| Entity Registrant Name | Affinity Bancshares, Inc. |
| Entity Central Index Key | 0001823406 |
| Entity Emerging Growth Company | true |
| Entity File Number | 001-39914 |
| Entity Incorporation, State or Country Code | MD |
| Entity Tax Identification Number | 86-1339773 |
| Entity Address, Address Line One | 3175 HIGHWAY 278 |
| Entity Address, City or Town | COVINGTON |
| Entity Address, State or Province | GA |
| Entity Address, Postal Zip Code | 30014 |
| City Area Code | 770 |
| Local Phone Number | 786-7088 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Ex Transition Period | false |
| Title of 12(b) Security | Common Stock, $0.01 par value per share |
| Trading Symbol | AFBI |
| Security Exchange Name | NASDAQ |
