In the US, a porch is at street level. (You walk from the street onto the porch, and then knock on the door) A house can have a front porch and a back porch. Porches are narrow, often for sitting in front of the house and watching the activity on the street. Porches usually are covered by a roof, and open tooutside air.
A balcony is always above street level. You cannot walk to the stre
I'd like to confirm differences as well, as we are currently arguing the point.
I'm Engilsh so a porch to me is a tiny anti-room before your front door to put shoes and wet clothing before going in, but I know that an American Porch is a raised deck around the front of your house where you might have such things as a swing chair.
We lived in a large house when I was growing up. There was a small outside area off the second floor. One might be able to sit out there or have plants. I consider an outside occupyable area above the main living area a balcony. In the same home we had a very large porch that could be enclosed by windows and or screens. The entire family could occupy it. It is more private than an outside