There is no fixed standard for the size of a handheld national flag, but it is generally recommended that it not exceed 2 meters. In international settings, the commonly used handheld flag size is size 3, which measures 93 cm in length and 60 cm in width.
The United States typically uses size 1, which measures 137 cm in length and 50 cm in width. When choosing the size of a handheld flag, the specific needs of the occasion should be considered; larger is not always better. Some events may require a larger flag, while smaller flags may be more suitable for other occasions.
