There are many different types of pie pans, the most popular ones are metal, aluminum foil, glass and ceramic. The type of pie pan you bake with is really just personal preference.
It's typically nine inches and perfect for a dessert pie. You could get four very generous slices or six regular slices. You should be able to get 6-8 slices of pie from a standard pie pan.
Deep-dish pie pans can be 10 inches or 12 inches and they’re great for fruit pies. You can usually serve 8 to 10 good slices from a deep dish pie pan.
I think baking a slab pie is lots of fun, doesn’t require a fussy pie crust and is a great choice for fruit or custard pies. Slab Pies can be baked on a cookie sheet.
How to calculate how many servings of pie you'll need, I calculate 1 1/2 pieces of pie per person and then multiply it by the number of people. Click the link for my easy calculation chart.