| Cover | Sep. 01, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Sep. 01, 2023 |
| Entity File Number | 001-36296 |
| Entity Registrant Name | Carisma Therapeutics Inc. |
| Entity Central Index Key | 0001485003 |
| Entity Tax Identification Number | 26-2025616 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 3675 Market Street |
| Entity Address, Address Line Two | Suite 200 |
| Entity Address, City or Town | Philadelphia |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 19104 |
| City Area Code | 267 |
| Local Phone Number | 491-6422 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.001 par value |
| Trading Symbol | CARM |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
