| Cover | Oct. 28, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | F&M BANK CORP |
| Entity Central Index Key | 0000740806 |
| Document Type | 8-K |
| Amendment Flag | false |
| Entity Emerging Growth Company | false |
| Document Period End Date | Oct. 28, 2021 |
| Entity Incorporation State Country Code | VA |
| Entity File Number | 000-13273 |
| Entity Tax Identification Number | 54-1280811 |
| Entity Address Address Line 1 | P.O. Box 1111 |
| Entity Address City Or Town | Timberville |
| Entity Address State Or Province | VA |
| Entity Address Postal Zip Code | 22853 |
| City Area Code | 540 |
| Local Phone Number | 896-8941 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
