What shape is Switzerland's national flag in normal official use? Square. Switzerland's national flag is a red square carrying a free-standing white Greek cross in its center, an unusual format because most national flags are rectangular. The square shape is explicitly specified in Swiss law for the national flag.
The design grew from the field signs used by soldiers of the Old Swiss Confederacy in the late 13th or early 14th century. The white cross identified Swiss combatants and later appeared on cantonal and military banners. Its modern national use developed during the Napoleonic era and was standardized through the 19th century.
A common mix-up involves Switzerland's civil and state ensign. That version, used by Swiss ships, boats and some non-governmental bodies, is rectangular with a 2:3 proportion. The national flag remains square. The only other sovereign national flag ordinarily recognized as square is Vatican City's, although practical display formats can vary.