How much cargo space do I need for a family road trip?

For a family of four on a week-long road trip, expect to need at least 30-40 cubic feet of cargo space with all seats in use. Most midsize SUVs offer 35-40 cubic feet behind the second row with seats up, which covers a typical family's luggage comfortably. If you are packing for 5-7 passengers in a 3-row vehicle, cargo space behind the third row drops to 15-21 cubic feet in most midsize SUVs, which is tight for more than a weekend trip. A cargo carrier or roof box is a common solution, though it reduces fuel efficiency. A vehicle with a large, flat load floor when seats are folded is more practical than one with a larger raw number that includes awkward wheel well intrusions.