How do I calculate the nutritional values of a recipe? I love to cook and experiment with recipes. While I'm aware that calories are not a perfect measure of what makes you gain weight and what doesn't, I would still love to have a rough idea of the energy values of the dishes I'm preparing, and ideally be able to fiddle with the ingredients just to see what happens to the calorie count.

How would I best approach this? 

My vision is that of a tool that


lets you enter a recipe's ingredients and amounts, and can calculate an approximate calorie count for the most common ingredients
ideally, lets you add other ingredients and their energy values?


I know for a fact there is software like this, but all the good products I've seen are for professional diet advisors, nutritional consultants and the like, and tend to be very expensive. 

I guess the basic functionality could be achieved with an Excel sheet, but where to get high-quality nutritional data from? Are there industry-standard databases for this?

This question matches mine in the title, but seems to be more about the calorie differences between cooked and raw food, which is not my concern.
Lose It!, a free weight-loss site, has this feature. To use it I think you need to start an account. To access it, you hit the Settings tab and then select Recipes in the left-hand column. Then select "New" and follow the prompts. This calculator allows you to enter the ingredients of a dish you are preparing. Most common ingredients will pop-up in the site's list with their respective caloric values. You can also manually enter in the values if you know them or if the ingredient is not in their list. You then set the "serving size" of your dish as its total volume. Then, when you enter in the amount you are eating into your daily food log, the site automatically shows you the caloric value of your portion.

The fifth screenshot here, shows you what it looks like.