quality:corruption, structural:scholar_edition, linguistic:translation, structural:expansion
Shapes and designs

Flags are usually rectangular in shape (often in the ratio 2:3, 1:2, or 3:5), but may be of any shape or size that is practical for flying, including square, triangular, or swallow tailed. A more unusual flag shape is that of the flag of Nepal, which is in the shape of two stacked triangles. Other unusually shaped flags include the civil flags of Ohio (a swallowtail); Tampa, Florida; and Pike County, Ohio.

Many flags are dyed through and through to be inexpensive to manufacture, such that the reverse side is the mirror image of the obverse (front) side, generally the side displayed when, from the observer's point of view, the flag flies from pole-side left to right. This presents two possibilities:

Some complex flag designs are not intended to be shown on both sides, requiring separate obverse and reverse sides if made correctly. In these cases there is a design element (usually text) which is not symmetric and should be read in the same direction, regardless of whether the hoist is to the viewer's left or right. These cases can be divided into two types:

Common designs on flags include crosses, stripes, and divisions of the surface, or field, into bands or quarters—patterns and principles mainly derived from heraldry. A heraldic coat of arms may also be flown as a banner of arms, as is done on both the state flag of Maryland and the flag of Kiribati.

The de jure flag of Libya under Muammar Gaddafi, which consisted of a rectangular field of green, was for a long period the only national flag using a single colour and no design or insignia. However, other historical states have also used flags without designs or insignia, such as the short-lived Soviet Republic of Hungary and the more recent Sultanate of Muscat and Oman, whose flags were both a plain field of red.

Colours are normally described with common names, such as "red", but may be further specified using colourimetry.

The largest flag flown from a flagpole worldwide, according to Guinness World Records, is the flag of the United Arab Emirates flown in Sharjah. This flag was 2,448.56 m (26,356.1 sq ft). The largest flag ever made was the flag of Qatar; the flag, which measures at 101,978 m (1,097,680 sq ft), was completed in December 2013 in Doha.