Comparing a dollar then to a dollar now

I'm writing a historical non-fiction book and I am having a hard time figuring out how much specific sums of money from the old days would be worth today. I came across this nice calculator at the Economic History Services site. The thing I learned is that there isn't one answer to the question "How much is $100 from 1960 worth today?" From the site:

In 2003, $100.00 from 1960 is worth:

$621.65 using the Consumer Price Index

$502.09 using the GDP deflator

$761.26 using the unskilled wage

$1,297.73 using the GDP per capita

$2,086.61 using the relative share of GDP

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