If you wanna do any industry, but don't feel like wasting time creating/maintaining spreadsheets, :

1. Go to Sequer.nl
2. Create an account
3. Add your character with current extensions
4. Update current market prices on materials
5. Select an item and it automatically calculates everything

I wonder why that fool Doek never said anything about this part of his website. It's awesome. \o/

Here's a screenshot how it looks: http://i.imgur.com/7rxSjkv.png