| Document and Entity Information | Jul. 19, 2024 |
| Entity Listings [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jul. 19, 2024 |
| Entity File Number | 001-40868 |
| Entity Registrant Name | Focus Impact BH3 Acquisition Company |
| Entity Central Index Key | 0001851612 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 86-2249068 |
| Entity Address, Address Line One | 1345 Avenue of the Americas, 33rd Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10105 |
| City Area Code | 212 |
| Local Phone Number | 213-0243 |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Written Communications | true |
| Soliciting Material | true |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Common Stock [Member] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | Units, each consisting of one share of Class A Common Stock and one-half of one Warrant |
| Trading Symbol | BHACU |
| Security Exchange Name | NASDAQ |
| Class A Common Stock, par value $0.0001 per share [Member] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | Class A Common Stock, par value $0.0001 per share |
| Trading Symbol | BHAC |
| Security Exchange Name | NASDAQ |
| Warrants, each whole warrant exercisable for one share of Class A Common Stock at an exercise price of $11.50 [Member] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | Warrants, each whole warrant exercisable for one share of Class A Common Stock at an exercise price of $11.50 |
| Trading Symbol | BHACW |
| Security Exchange Name | NASDAQ |
