Coat of arms of Switzerland in the context of "Swiss Army knife"

The national flag of Switzerland displays a white Greek cross in the center of a square red field. The white cross is known as the Swiss cross or the federal cross. Its arms are equilateral, and their ratio of length to width is 7:6. The size of the cross in relation to the field was set in 2017 as 5:8. Alongside the flag of Vatican City, the Swiss flag is one of only two square national flags in the world.

The white cross has been used as the field sign (attached to the clothing of combatants and to the cantonal war flags in the form of strips of linen) of the Old Swiss Confederacy since its formation in the late 13th or early 14th century. Its symbolism was described by the Swiss Federal Council in 1889 as representing "at the same the Christian cross symbol and the field sign of the Old Confederacy". As a national ensign, it was first used during the Napoleonic Wars by general Niklaus Franz von Bachmann, and as regimental flag of all cantonal troops from 1841. The federal coat of arms (eidgenössisches Wappen) was defined in 1815 for the Restored Confederacy as the white-on-red Swiss cross in a heraldic shield. The current design was used together with a cross composed of five squares until 1889, when its dimensions were officially set.