| Document And Entity Information | Nov. 04, 2022 |
| Document Information [Line Items] | |
| Entity, Registrant Name | PATRIOT NATIONAL BANCORP, INC. |
| Document, Type | 8-K |
| Document, Period End Date | Nov. 04, 2022 |
| Entity, Incorporation, State or Country Code | CT |
| Entity, File Number | 000-29599 |
| Entity, Tax Identification Number | 06-1559137 |
| Entity, Address, Address Line One | 900 Bedford Street |
| Entity, Address, City or Town | Stamford |
| Entity, Address, State or Province | CT |
| Entity, Address, Postal Zip Code | 06901 |
| City Area Code | 203 |
| Local Phone Number | 252-5900 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | PNBK |
| Security Exchange Name | NASDAQ |
| Entity, Emerging Growth Company | false |
| Amendment Flag | false |
| Entity, Central Index Key | 0001098146 |
