I've made a pizza today and thought the dough could use a little more salt. I've looked at this answer and have a question about the salt ratio. How is it calculated? The percentage of flour, or the percentage of dough?  My pizza recipe calls for 300 g flour, 150 ml water and 3 g salt. That is 1% of the flour weight, but less of the total weight. If 3% is the recommended salt level for bread, I should be using 9 gr for the flour, or 13,5 g for total weight. That is a huge difference.  Edit: The recipe calls for 1 tablespoon of salt, 1 bag of dry yeast (but I use my own mother dough), and 60 ml oil.  Edit: I believe I measured one tablespoon to be 3g :-( 
When you have a (good) bread recipe, the weight ratio is always given as percentage of the flour. This tradition is known as a baker's percentage. It may sound counterintuitive at first, but when you are measuring, or scaling, ingredients (which add to the total weight by themselves) you soon notice how convenient it is.   So, if you recipe calls for 300 g flour and 3% salt, it needs 9g salt. The water at 150 ml is 50% - a rather low hydration, don't do this with bread flour unless you have another liquid in the recipe you didn't mention (eggs, oil, or additional water for a poolish). It will be stiff with AP flour, but I like it that way, while other people find it too hard. It is up to personal preference, I guess. Also measure the other ingredients (yeast) as a percentage of the flour weight. And if you are given a recipe for fresh yeast, don't forget to convert it to instant dry if you are using it, or vice versa - the conversion factor is 3:1.  