I found that calculating the costs of all the ingredients/boards/time to make a cake was easy, but was left a little overwhelmed at calculating electricity/gas costs for my gas range oven. I know some of you must have been experiencing the same so I found this article that includes a nice little chart about halfway down the page which predicts electricity/gas usage for several different oven types! Of course you need to look at your bill and figure out the exact rate for a kW or therm of your electricity or gas, but I found this very helpful! Hope you do too! 

http://michaelbluejay.com/electricity/cooking.html

Thank you so much for posting this!  I was thinking I'd have to bust out some serious math to figure this out.

The way to do anything similar is to keep your old bills. As you should if your running a legit business. Add up last years electric bills (or water bills, or gas bills, etc....) and divide by 12= average cost per month.

That is true if you have a store with all the bills going towards your business. This is good for cottage law/ licensed home bakers who share their bill with personal expenses. This can help determine how many actual kW are going towards your business. 

AI can log in to my account online and see my daily usage and cost, which makes it easy to work out how much a day of baking cost in electricity.