Hopefully by the time I get my bronco the world will be in a happy place and not putting saleable gas in tanks for war.Your in the ballpark. Let's the just say you get 20 miles per gallon. And you average 10,000 miles per year. You are looking at 500 gallons. 500 x 4 = 2000. But not likely to get 20 miles per gallon and good luck on 4 dollars per gallon of gas.