Ford has released official fuel economy ratings for its new diesel-powered F-150 and it has now become the most fuel-efficient half-ton in the segment.

The two-wheel drive 2018 Ford F-150 3.0-liter diesel is rated at 30 mpg highway, 22 in the city and 25 mpg combined, beating out the next most efficient half-ton truck, the Ram 1500 EcoDiesel, which nets 27 mpg on the highway and 23 combined.

READ MORE: Ram 1500 EcoDiesel to Return in 2019, Already Claims to be Efficiency King

When equipped with four-wheel drive, the diesel F-150 is rated at 20 mpg city, 25 on the highway and 22 combined. The Ram 1500 EcoDiesel, when equipped with four-wheel drive, matches the Ford with a combined mpg rating of 22, though the Ram beats the F-150 on the highway with its 27 mpg rating, and loses to it in the city by one mpg, with a rating of 19.

Power comes from a 3.0-liter diesel that makes 250 horsepower and 440 lb-ft, good for a maximum tow rating on the diesel model of 11,400 pounds when the truck is outfitted as a 4×4, Regular cab XL model.

The new diesel-powered F-150 is going to head to dealers in May 2018.