My husband drives it every day to work about 15 miles and back and it takes him 2 weeks to go through a tank. With the trailer with one horse I have driven it about 290 miles before having to fill up and that was going uphill. Coming back with an empty trailer I only used 3/4 of a tank. I think it has a 30 gallon tank. The thing about diesels are that they are really only good and broke in at around 100,000 miles. We bout ours with that many miles on it and didn't think twice because it was a diesel. Most gas trucks would be close to the end at that point.