Profit is what's left over after you pay your bills, and pay your wages. What's left is your profit. The numbers you find as you do this are your ' indicators' . It's like drawing a road map. If your hourly wage doesn't add up, trim the fat from your processes and find a way of working faster and cheaper.
Beginners usually underprice their product.
The only good formula is one which will work across the board, - and will work for almost everyone. You will never know if you are making a profit if you don't walk the walk. So saith ElJay the Web-Dancing Frog.