Googling only tells me there was a 12billion $ assistance from the united states to european countries, but is that 12 billion using today’s value of the dollar, or 1948’s dollar value (which would mean in current times this would be around 128billion according to converters)
sorry if this isn’t the right sub for this, nothing else came to mind
$12 billion of assistance refers to the 1948 value of the dollar, this is the general rule for any figures you see quoted in historical context, unless otherwise stated at the source. $12 billion in today's money wouldn't even begin to fund the rebuilding of Europe necessitated by war.
Following the war, a November 1947 report by the President's Committee on Foreign Aid, headed by Averell Harriman at the request of Harry S. Truman, found that somewhere in the region of $12.5 to $17.2 billion would be required to assist Europe. By 1946, $9 billion had been spent on emergency and humanitarian aid by the US. Most of this - $3.75 billion - went to the United Kingdom in 1946, to stabilise the value of the pound sterling against other nations' reserves of sterling in the Empire, such as India and Pakistan.
In today's money, this means $49,143,846,153.85 was sent to the UK in 1946, and the U.S. had spent $117,945,230,769.23 by 1946. Pretty eye-watering figures!
Sources
Bruce L.R. Smith, 'Birth of the Marshall Plan, 1947-48,' in Lincoln Gordon: Architect of Cold War Foreign Policy, (University Press of Kentucky: 2015).
Inflation calculator: https://www.usinflationcalculator.com