While en route to the destination airport, the airplane’s engine lost power. The pilot switched fuel tanks and was able to restore engine power but the engine lost power a second time. The pilot was unable to glide the airplane to the runway and the airplane collided with trees short of the runway. The left wing separated from the fuselage and the right outboard fuel tank separated from the wing resulting in substantial damage. A review of the pilot’s preflight fuel calculations found that the pilot estimated that the airplane had 70 gallons of fuel onboard for the flight. Using an electronic flight bag, the pilot calculated the direct route of flight would be 430 nautical miles (nm), last an estimated 3 hours and 17 minutes, and require about 50 gallons of fuel, assuming 15 gallons per hour as stated in the pilot operating handbook. After departure, the flight required several course deviations and altitude deviations due to weather, which resulted in the flight lasting over an hour longer than planned. The altitude deviations required additional fuel burn that was not included in the calculations. While in flight, the pilot considered his fuel remaining about 170 nm from his intended destination, but estimated he had enough fuel to make his destination. The pilot stated that there were no mechanical anomalies with the airplane or engine that would have precluded normal operations.