I recommend making the legs of your carport at least one foot taller than the tallest vehicle you plan to own. Remember to include roll bars, top racks, and RV AC units in your height measurements.
Note: If you close the gables of your carport, the clearance will be about three inches less than the leg height. For example, if your carport’s legs are 7’, the clearance will be about 6’ 9”.
If you leave the gables open, the maximum clearance will be at the center brace, near the peak of the roof. This is a little more than two feet higher than the leg height. From the top brace, the roof frame tapers down to about the height of the legs at each side. So if you have a carport with 7’ legs, you can park a vehicle under it that is a little taller than 7’, as long as you don’t park too close to either side.