For homes, saunas are typically smaller, ranging from 1 to 4 persons. In commercial settings, saunas typically range from 6 to 12+ people.
As a frequent sauna user in saunas all over the place (hotels, gyms, spas), the usual size is 4 to 8 people with 8 being fairly large.
What is my favorite sauna layout?
I like the L-shaped sauna layout where both arms of the bench have two levels. I find the L-shaped layout is easier to talk with other people instead of one long straight bench.
Another dimension I like is one long bench – spanning at least 7 to 8 feet so that I can fully lie down.
Check out the graphic below. As you can see, small saunas start with a 48″ long bench and expand to huge 12 foot long U-shaped saunas and everything else in between.