How much does a cup of flour weigh?
I weigh flour when preparing many of my recipes, because it is the easiest, most accurate way to measure. There are some recipes, however, especially those calling for all purpose flour, where I don't weigh the flour, because it's not a big factor in the product's outcome.
For those that don't have a scale, I put in the approximate volumetric measurements in the recipe. One cup of bread flour is approximately 4.7 ounces (at least today it was). For example, if you look at my French Bread recipe, 10 ounces of bread flour is approximately 2 cups and 14 ounces is approximately 3 cups. I say approximately, because if you repeatedly measure 1 cup of flour and then weigh it on a scale, its weight may vary, because flour settles and compacts in varying amounts. When you put flour in a measuring cup, you may be measuring air, which is not going to be what you intended to measure. Weighing eliminates the problem of flour settling. Even if you weigh the flour when preparing a bread/pizza dough, it's best to expect that you may still need to adjust the water or flour amounts, because there are so many factors including, humidity, strength of the flour, etc, that can effect your dough's consistency.
When using one of my recipes that call for a measure of flour by volume, stir the flour, scoop it into the cup and then level it off.
Here's a short video demonstrating how I use my (inexpensive) digital scale. Hope you find it helpful.