Original: The act specified that new flag designs should become official on the first July 4 ( Independence Day ) following admission of one or more new states . The most recent change , from 49 stars to 50 , occurred in 1960 when the present design was chosen , after Hawaii gained statehood in August 1959 .
Simplified: Hawaii joined on 21 August 1959 so the flag with 50 stars that is used today was not flown until 4 July 1960 .