“The biggest single component of retail gasoline prices is the cost of the raw material used to produce the gasoline – crude oil. Recently, that price has ranged between $50 and $70 per barrel, depending on the type of crude oil purchased. With crude oil at these prices, a standard 42 gallon barrel translates to $1.19 to $1.67 per gallon at the pump. Excise taxes add another 49 cents a gallon on average nationwide.
There are additional costs to refine, transport, and sell gasoline at retail outlets. As of January 2019, crude oil costs accounted for 53 percent of what people are paying at the pump per the U.S. Energy Information Administration. Excise taxes averaged another 17 percent. That leaves 30 percent for the refiners, distributors, and retailers.”
From here:
https://gaspricesexplained.com/#/?section=gasoline-taxes-by-state
Link includes a US map of gas taxes by state (IOW, your results may vary)
You don’t get 42 gallons of gasoline from a 42 gallon barrel of crude oil. That number is around 19 to 20 gallons of gasoline per barrel and around 11 gallons of diesel.