General form of registration statement for all companies including face-amount certificate companies


6 Months Ended
Jun. 30, 2021
Cover [Abstract]  
Document Type S-1
Amendment Flag false
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
Entity Filer Category Non-accelerated Filer
Entity Small Business true
Entity Emerging Growth Company true
Elected Not To Use the Extended Transition Period false