How many kids does it take to make a birthday party 'worth it'?

Summertime is the season of birthdays at our home. All of our boys' birthdays fall between the end of school and the middle of July. Over the years, we have experimented with ideas for birthday celebrations. Sometimes we have a quiet get-together with our family. Other years, we have them invite a friend to a movie and buy their favorite takeout food. Then there are the years we do a full-fledged birthday party (read: spend more money).

So, as the birthday season begins at our home this month, we have to decide which it is going to be this year...small parties, big parties, or no parties at all. So, business person that I am, I decided to do a little math to help us make the decision.

Let's start with a question: How many kids does it take to make having a birthday party worth it (economically speaking, at least)?

And we need a scenario: You and your spouse take 10 kids to a pizza place (you know, the kind with the video games, characters that dress as animals, and the prize booth where the kids can trade in the tickets they earn on the games for anything from the inventory of Oriental Trading Company) for a birthday bash.

Here is an itemization of the true cost of the party as well as the return on the investment:

• 7 hours of parents time (1 to make and deliver invitations, 2 for party preparations, 3 for the party itself, and 1 for cleanup) at $50 per hour per parent: $700 total
  
• Invitations and postage (or gas, if you deliver them in person): $25 total
  
• Fee charged by the pizza place for food, drinks and game tokens: $20 per kid x 10 kids: 200, plus 8% tax: $216 total
  
• Party favors for the kids attending (this is a strange concept to me, but my wife insists it is normal--give the kids who come to the party gifts of their own): $5 per kid x 10 kids: $50 total
  
• A chiropractic adjustment for both parents after the party: $50 times two parents = $100 total
  
• A therapy session for two siblings of the child who had the party (because they were traumatized that they only got to go to the bouncy-thing place for their birthday party, which was not as good because it did not have a small human dressed as a stuffed mouse at it): $100 per session times two children: $200 total
  
• Liability insurance, in case any of your kid's friends' parents sue you when their child gets injured by the small, rotating helicopter ride at the party: $65 total
  
• Extra tokens for the birthday child, because you want them to have more than the 7 tokens each of the other children got as part of the package: $20 total
  
• Cake that you bring in for the party, since they party package does not include cake: $20
• Gratuity for the teenager that helps facilitate the party's arrangements (What! When I learned that this was expected, I couldn't believe it): $25 total
  
• Child care for all of your children after the party so the parents can get some rest: $35 total
  
• Replacing the toy truck your son received as a gift from a friend when it breaks 1 hour after the party ends: $10 t0tal
  
• Total cost of party: $1466
  

Return on investment:

• 8 of the children bring a gift for your child, averaging $10 per gift: $80 total
  
• A 1-inch bouncy ball and plastic spider for each of the 10 children from the prize stand at the pizza place: $0.50 total (if that)
• Endless smiles and happy memories for your child (priceless--so, it doesn't count in this example, since it is strictly 'economically speaking').
  

As is clear in the example, the pizza party with 10 kids ends up costing you about $1,385.50 more than it returns in economic value, and is definitely NOT WORTH IT!

How do you turn this scenario around and break even? How many kids would you need to invite to the party, assuming each gift they bring costs an average of $10? The answer may surprise you...it is impossible to make it worthwhile economically. Even if you invite 1000 kids, since each one you bring costs you $25 more dollars (a $20 party fee to the pizza place and $5 fee for their party favors) while the gift they bring is worth $10.00-- the more kids you invite, the worse off you are.

Use this simple formula to do the math yourself: 25x+1216=10x*0.8

So, it appears your only solution is if the guests bring gifts that are worth more than $10 a piece (please don't invite my kids to such a party, by the way; I'm not paying more than $10 for a party gift). How much would they need to spend on each gift to make it worth it? Calculate it yourself, if you like, using this this formula: 25x + 1216=yx*0.8 (where x is the number of kids attending and y is the cost per gift).

If you invited 10 kids, each of their gifts would need to be worth about $150. If you invited 100, each would need to be worth about $40. If you invited 1000 kids, each gift would need to be about $25. Then, a strange things starts to happen with the math. Make it 100,000 kids, and then 1,000,000 kids--the price per gift needed never drops below $25 per gift (because $25 is the real variable in the equation representing the admission price and party favor).

So, I figured we'd be safe if we invited just 1000 kids and insisted on a minimum gift value of about of $25 per kid, since anything more than 1000 doesn't change the result much.

And the cost for the party would be $26,216. but don't worry, it would produce $26,216 worth of gifts for your child! (And that is just to break even--if you want to MAKE money on the event, you'll have to increase the value-per-gift requirement).

If you'd like to follow this strong economic advice, I've gone ahead and included an invitation template for you to use:

Please join Johnny and 999 of his closest friends at the world's largest pizza restaurant for an evening of fun and games.

While you may have to wait in a long line to have a turn on the Ski Ball game, please know that you will receive a $5.00 party favor bag in exchange for pretending to be friends with our child.

Please make sure you bring a gift that worth at least $25.00 (or if less than $25.00, please bring the cash difference in value and give it to Johnny's parents).

RSVP by next Tuesday so that we can decide whether this party is economically viable (formulas available upon request for any interested parents).

After all of this dizzying analysis, I have decided we'll just give each of the kids $100 instead of a party and tell them to spend it however they would like. After all, they would be saving us a ton of time and money.