The 385-hour private pilot reported that the fuel tanks on the single engine airplane were topped off with 90 gallons of aviation fuel for the 874.6 nautical mile cross country flight that originated at 0900. At 1530, while the airplane was in cruise flight about 10 minutes from his intended destination, the engine lost power. The pilot elected to execute a forced landing to a rough, mesquite covered field. The airplane sustained structural damage during the forced landing; however, the pilot and his passenger were able to egress from the airplane unassisted. The FAA inspector who traveled to the accident site discovered that the fuel cells were empty. The pilot added that he "ran out of fuel" and he had relied on a fuel computer that indicated there was 14 gallons (1.1 hours) of fuel remaining when the engine lost power. He added that the engine power loss could have been prevented if he had used a fuel burn rate of 13 gallons per hour and had restricted his endurance to a maximum of 6 hours.