Depends. If I keep it under a certain speed, the eco drive kicks in and my mpg skyrockets, but avg 21 mpg at 18 gallons. 378 miles by that math, reality: I can put in 16 gallons when the low fuel light comes on, 320 or so miles into the tank. But I put on a new exhaust last week, and my car is known for being sensitive to exhausts, it tends to go up almost 10% with the right one. I'll fill it up tonight and find out.
My rig at one job gets 2.9 mpg and holds 35 gallons iirc.
My rig at my other job goes about 1100 miles to 190 gallons.