I am baking a nine inch round and a six inch round for a child's birthday party this weekend. Do you think this will be enough to serve 25-30 people? Or should I bake some cupcakes just in case?

My chart says you should have enough, but I would like to add that I have to consider the appetites that I'm serving. Example: this serving size is perfect for my Mother and great Grandmother, however my husband and teenage boys will swallow two piece this size.

Size of round cake:   Servings: 4" x 2" x 1 3/8"  
6   10  
8   18  
9   23

If I had a bunch of big eaters, I think I would make 6-12 cupcakes. If they are 'polite' eaters you should have enough, with a little to spare. I hope this helps a little.