| Document and Entity Information | Mar. 24, 2022 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001832351 |
| Document Type | 8-K |
| Document Period End Date | Mar. 24, 2022 |
| Entity Registrant Name | Fast Radius, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-40032 |
| Entity Tax Identification Number | 85-3692788 |
| Entity Address, Address Line One | 113 N. May Street |
| Entity Address, City or Town | Chicago |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60607 |
| City Area Code | (888) |
| Local Phone Number | 787-1629 |
| 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 | false |
| Common Stock Par Value 0.0001 Per Share 2 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, par value $0.0001 per share |
| Trading Symbol | FSRD |
| Security Exchange Name | NASDAQ |
| Warrants Each Whole Warrant Exercisable For One Share Of Common Stock At An Exercise Price Of 11.50 Per Share 1 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Warrants, each whole warrant exercisable for one share of common stock at an exercise price of $11.50 per share |
| Trading Symbol | FSRDW |
| Security Exchange Name | NASDAQ |
