Use the CIA World Factbook to locate the nominal gross domestic product of the country whose real gross domestic product you would like to compute. Assign the variable 'N' to this value and 'Q' to the unknown real gross domestic product. (See References 1)
For example, the nominal gross domestic product of Iceland in 2008 was $13.15 billion.
N = 13,150,000,000
Q = ?
Find your country's gross domestic product price index, also called its gross domestic product deflator, using the search function of the International Monetary Fund's website and assign this value the variable 'P.' (See References 1)
The gross domestic product price index for Iceland in 2008 was 145.338.
P = 145.338
Divide 'P' by 100. (See References 1)
[P/100]
145.338 / 100 = 1.45338
Divide 'N' by the quotient, or division product, of 'P' and 100 to find 'Q.' (See References 1)
(N) / (P/100) = Q.
13,150,000,000 / 1.45338 = Q
Q = $9,047,874,609
This means that the real gross domestic product of Iceland in 2008 was just below $9.3 billion.