Teffanie, will there be more adults at the party or your son's friends? Kids will eat more(and also waste more) then the adults.

I think there will be more kids

Don't forget dessert and drinks. When we had our granddaughters graduation last year we served a big sheet cake, and colas, water both plain and flavored, iced tea, too. We all had so much fun. It was more of an open house, we served barbecue sandwiches which we made in advance in a slow cooker and also used that to keep it warm. We ate both inside and outside. There is a site that can assist you in how much you need, but I'm sorry I couldn't find it.

I think the site grandmamary is thinking about may be "Growlies for Groups" :
http://www.angelfire.com/bc/incredible/indexhundred.html

Thanks everyone for the advice

Hi Teffanie, for the punch I would make 4-5 gallons (4 gallons is 128- 4 ounce servings, which is what most ladle sizes are). It is easier to have left over soda and water storage wise then trying to store Punch. So you may even want to reduce that amount by a gallon. For the Hot Dogs I would get 100 (They aren't as popular as hamburgers) Hamburgers, figure not more than 200 patties. People take Potato Salad more than Coleslaw and Baked Beans. I would have 7-8 gallons of that ( 8 oz. portions make 128 servings). Baked Beans have 4 gallons( 4 oz. portion makes 128 servings) and lastly Cole slaw, have 3-4 gallons. ( 4 0z. portions makes 96 servings for 3 gallons). Not everyone is going to sample everything provided. I wouldn't make 150 portions of everything. With the exception of the hamburgers. You are going to have snacks and chilli too. This gives you some measurements to think about. Have fun and congratulations to your son! NancyLouise

Thanks colleenoz that is the site I was trying to remember. Don't forget cups too. My daughter in law went to a store called party city and bought all the paper products in school colors. If the graduate is going to a college you could even decorate with the colors of the school too. We also had a smaller table set up with her school accomplishments and photos of her growing up. We also borrowed chairs and tables from her work so that was a big help. I was surprised that my small house could seat so many people. lol Don't fuss over it and have a good time. Make sure you have plenty of toliet paper. You will find with that many people your bathroom will be used a lot. Cars were also a problem we had them everywhere. We invited our neighbors so that we could use their driveways if we needed extra parking. Mary