Annual report pursuant to Section 13 and 15(d)


Cover - USD ($)
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Apr. 01, 2024
Jun. 30, 2023
Cover [Abstract]        
Document Type 10-K      
Amendment Flag false      
Document Annual Report true      
Document Transition Report false      
Document Period End Date Dec. 31, 2023      
Document Fiscal Period Focus FY      
Document Fiscal Year Focus 2023      
Current Fiscal Year End Date --12-31      
Entity File Number 333-193087      
Entity Registrant Name FOCUS UNIVERSAL INC.      
Entity Central Index Key 0001590418      
Entity Tax Identification Number 46-3355876      
Entity Incorporation, State or Country Code NV      
Entity Address, Address Line One 2311 East Locust Court      
Entity Address, City or Town Ontario      
Entity Address, State or Province CA      
Entity Address, Postal Zip Code 91761      
City Area Code (626)      
Local Phone Number 272-3883      
Title of 12(b) Security Common Stock, $0.001 par value      
Trading Symbol FCUV      
Security Exchange Name NASDAQ      
Entity Well-known Seasoned Issuer No      
Entity Voluntary Filers No      
Entity Current Reporting Status Yes      
Entity Interactive Data Current Yes      
Entity Filer Category Non-accelerated Filer      
Entity Small Business true      
Entity Emerging Growth Company false      
Entity Shell Company false      
Entity Public Float       $ 47,304,201
Entity Public Float     64,771,817  
ICFR Auditor Attestation Flag false      
Document Financial Statement Error Correction [Flag] false      
Auditor Firm ID 572 6906    
Auditor Name Weinberg & Company, P.A. Reliant CPA PC    
Auditor Location Los Angeles, CA. Newport Beach, CA