I think I can help you Rose. You said "recipes" so I am assuming that you are making them from scratch rather than a box. So with that information you would need to know how many cups of batter your recipe yields. Easiest way I know is to make it and measure it out. Once you know this the sizes go something like this:

6-inch pan = use 2 cups batter = bake 40-50 minutes
8-inch pan = 3 1/2 cups batter = bake 40-50 minutes
10-inch pan = use 5 cups batter = bake 40-50 minutes
12-inch pan = 7 1/2 cups batter = bake 45-55 minutes
14-inch pan = 10 cups batter = 45-55 minutes
16-inch pan = 13 cups batter = 45-55 minutes

And just in case I assumed wrong or someone else would like to know, one boxed cake mix yields about 5 cups. Hope it helps!