| Cover | May 17, 2021 |
| Entity Addresses [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | May 17, 2021 |
| Entity File Number | 001-38633 |
| Entity Registrant Name | BM TECHNOLOGIES, INC. |
| Entity Central Index Key | 0001725872 |
| Entity Tax Identification Number | 82-3410369 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 201 King of Prussia Road |
| Entity Address, Address Line Two | Suite 350 |
| Entity Address, City or Town | Wayne |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 19087 |
| City Area Code | (877) |
| Local Phone Number | 327-9515 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
| Class A Common Stock | |
| Entity Addresses [Line Items] | |
| Title of 12(b) Security | Class A Common Stock |
| Trading Symbol | BMTX |
| Security Exchange Name | NYSEAMER |
| Warrants to purchase Class A Common Stock | |
| Entity Addresses [Line Items] | |
| Title of 12(b) Security | Warrants to purchase Class A Common Stock |
| Trading Symbol | BMTX.W |
| Security Exchange Name | NYSEAMER |
| Former Address [Member] | |
| Entity Addresses [Line Items] | |
| Entity Address, Address Line One | Megalith Financial Acquisition Corp. |
| Entity Address, Address Line Two | 535 5th Avenue |
| Entity Address, Address Line Three | 29th Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10017 |
