The Subaru Forester and Outback are primarily differentiated by their size, exterior design and handling. The Outback is closer to a traditional wagon in exterior design and has car-like handling qualities, while the Forester is designed to more closely mimic the appearance and driving qualities of an SUV.
The 2015 Subaru Forester is based on the compact Impreza platform, while the Outback is based on the larger Legacy platform. This makes the Outback longer than the Forester by 8 inches and wider by 2 inches. The wheelbase of the Outback is 4 inches longer, resulting in a smoother ride as compared to the Forester. While both vehicles have 9 inches of ground clearance, the Forester is 2 inches taller than the Outback. This translates both into a higher driving position and a more SUV-like ride in the Forester due to its slightly higher center of gravity.
The extra height of the Forester gives it slightly more cargo room than the Outback. The Forester has 74.7 cubic feet of cargo space with the rear seats folded down, versus the 73.3 cubic feet of space available in the Outback. However, the longer wheelbase of the Outback makes its front passenger seats more roomy than those in the Forester.