Compare diesel and gasoline costs.
Diesel and gasoline cannot be compared on pump price, because the two fuels do not deliver the same distance per gallon. Diesel contains around 13% more energy per gallon and diesel engines run at higher compression, so a diesel version of the same car typically returns 20 to 30% better economy — which is what has to offset its higher price at the pump. The comparison that settles it is cost per mile: fuel price divided by mpg. At 4.10 diesel and 38 mpg that is 10.8 cents a mile against 11.7 cents for gasoline at 3.50 and 30 mpg, so diesel wins narrowly on fuel. Note this covers fuel only — diesel maintenance, particulate filters and urea top-ups all sit outside it.
Diesel vs Gas Cost
Annual cost = miles / mpg x price per gallon for each fuel; cost per mile = price / mpg; difference = |diesel - gasoline|
On fuel alone, usually yes for high-mileage highway driving, where the economy advantage is largest. Once maintenance, particulate filter issues and urea are included, the gap narrows or reverses for low-mileage urban use.
Broadly above 12,000-15,000 miles a year with a highway bias. Short urban trips prevent the particulate filter regenerating, which turns the fuel saving into a maintenance bill.