The Norwegian flag was designed in the 1821. It is based on the Danish flag, the Dannebrog, marking the union with the Kingdom of Denmark from 1397 until 1814. The blue cross symbolises the union between Norway and Sweden from 1814 until 1905. The Norwegian flag is also used in Jan Mayen and Svalbard, which are both parts of the Kingdom of Norway.
The official red colour is Pantone 200, which corresponds fairly accurately to the digital colours:
Hex: #BA0C2F R: 186 G: 12 B: 47 CMYK: 0, 100, 76, 13
The official blue colour is Pantone 281, which corresponds fairly accurately to the digital colours:
Hex: #00205B R: 0 G: 32 B: 91 CMYK: 100, 78, 0, 57
The proportional measurements for the length are: 6,1,2,1,12
The proportional measurements for the height are: 6,1,2,1,6