The flag of Norway is red with a blue Scandinavian cross outlined in white that extends to the edges of the flag; the vertical part of the cross is shifted to the hoist side in the style of the Dannebrog, the flag of Denmark. The proportions of the national flag are 22:16 (width to height), its colour elements having a width of 6:1:2:1:12 and a height of 6:1:2:1:6. The proportions of the state flag are 27:16, or 6:1:2:1:6:11 horizontally and 6:1:2:1:6 vertically.
The red colour shall be PMS 032 U and the blue PMS 281 U in the Pantone system. This approximates to the RGB values #EF2B2D (red) and #002868 (blue).
It is difficult to establish what the earliest flag of Norway looked like. During ancient times countries did not fly flags. Kings and other rulers flew flags, especially in battle. Saint Olav used a serpent within a white mark at the Battle of Nesje. Prior to this the raven or dragon was used. Magnus the Good used the same mark as Saint Olav. Harald Hardråde used a raven. Inge used a red lion on gold. Sverre used an eagle in gold and red. The earliest known flag which could be described as a national flag of Norway is the one used today as the Royal Standard. Eirik Magnusson used a flag described as a golden lion with axe and crown on red from 1280 and this was since regularly the flag of Norway and of the King of Norway.
The flag is based on the Coat of Arms and was originally only a flag for the ruler of Norway (as it is today). It was later also used on ships and on fortresses until it was gradually phased out during the 17th and 18th centuries. Its earliest certain depiction is on the seal of duchess Ingebjørg in 1318. Around 1500 it became the custom for ships to fly the flag of their home country to identify their nationality. At least as late as 1698 the lion banner was flown over Akershus Fortress. The "Norwegian lion" was placed in the colours of all the Norwegian regiments in 1641. In 1748 a decree stated that the Dannebrog should be the only legal merchant flag.
From about the 16th century until 1814 Norway used the same flag as Denmark, as it was in union with that country. In 1814 independent Norway adopted the Danish flag with the Norwegian lion in the hoist. This flag was in use until 1821. In 1814 Norway was united with Sweden and in 1815 a common flag for both states was introduced, the Swedish flag with a white cross on a red background in the top left corner (or canton) of the flag. This design was used for government flags and for merchant ships beyond Cape Finisterre. A distinctive Norwegian flag was designed in 1821 by Fredrik Meltzer, a member of the parliament (Storting).
Until 1838 the design was only used in Northern waters, as Norway had no treaty with the Barbary pirates of North Africa. In 1844 a union badge combining Norwegian and Swedish colors was placed at the hoist of both countries' flags. The badge was popularly called Sildesalaten ("the herring salad") from its resemblance to a herring salad. Initially, the union flag was popular in Norway, since it clearly denoted the equal status of the two united states. As the union with Sweden became less popular, the Norwegian parliament abolished the union badge from the national (merchant) and state flags in 1898. Although the law was not approved by the King, it became effective since it had been passed by three different Stortings. The new flag was first flown in 1899. At the dissolution of the union in 1905, the badge was removed from the navy flag as well. Sweden kept it in all flags until 1905.
Laws regarding the flag
The Norwegian flag law of 1898  specifies the appearance of the merchant and state flags and their use by merchant ships, customs and post vessels. The flag regulations of 1927  further describe the use of the state flag on state property and on national holidays.
The flag regulations also describe the time of day when the flag should be drawn. From March to October the flag should be drawn from 8.00. From November to February it should be drawn from 9.00. The flag is drawn until sunset, although no later than at 21.00. if sunset is later than that. In the northern counties Nordland, Troms and Finnmark the flag is drawn between 10.00 and 15.00 from November to February. These rules do not apply for private use of the flag, but they are still usually observed for that use of the flag as well.
There also exist some unwritten rules about things like how the flag should be folded, that it should never touch the ground, and not be worn on the body below the waist.
The Sami flag is now regarded as official, and can be used in addition to or instead of the Norwegian flag on Norwegian flag days as well as the Sami flag days, and other occasions where the use of flag is natural. The rules for when that flag should be used on public buildings are the same as for the Norwegian flag, with the exception that if the Sami flag is used together with the Norwegian flag on official flag days or official occasions (both Norwegian and Sami), the Sami flag should be drawn on the flag pole to the right of the Norwegian flag .
Fredrik Meltzer chose a Christian cross, following the tradition of other Nordic countries (Denmark and Sweden). Red, white and blue were chosen to denote democracy, as these colours were used in the flags of comparably democratic states (The Netherlands, United Kingdom, The United States, and France). Meltzer's design also refers to the red and white Danish flag, which had been Norway's flag as well until 1814. The blue cross was probably a reference to the blue of the Swedish flag.
Norwegian flag days
January 1 - New Year's Day
January 21 - Princess Ingrid Alexandra's birthday
February 6 - The Sami National Day. (An official flag day both for the Sami people and for the whole of Norway.)
February 21 - King Harald V's birthday
May 1 - Labour Day
May 8 - Liberation Day 1945
May 17 - Constitution Day 1814 (National Day)
June 7 - Independence Day 1905
July 4 - Queen Sonja's birthday
July 20 - Crown Prince Haakon Magnus's birthday
July 29 - Olsok. (Olav's Mass. In memory of King Olav Haraldsson (the Holy), who died in the battle of Stiklestad July 29, 1030.)
August 19 - Crown Princess Mette-Marit's birthday
Second Monday of September every 4 years - General election
December 25 - Christmas Day
In 1821 the Norwegian parliament (Stortinget) adopted the flag Norway uses today as the flag of Norway. However the King refused to accept the new flag. That started a period of flag confusion. The flag could only be used north of Cape Finisterre, Spain because the foreign service of the King refused to pay North African pirates to recognize it. In stead the Swedish flag was used until 1844. In 1844 the new Norwegian flag was approved by the King with the addition of a union mark (this mark was also added to the Swedish flag). In 1898 the Storting resolved to "purify" the flag and adopted a new law regarding the merchant/civil flag. The state/war flag had the union mark until 1905.
It is important to note that the use of flags on land (other than in battle) is fairly new.