You replace the “regular” flour with an equal amount of oat flour by weight, not by volume. This is when a kitchen scale comes in really handy. Oat flour is significantly lighter than all-purpose and whole wheat flour.
Can I replace oats with flour? Oats are low in fat, and are sodium free, cholesterol free and preservative free. When baking, you may substitute oats for up to one-third the amount of flour called for in the recipe using either Quick or Old Fashioned Oats.
Can I use all purpose flour instead of oat? Many recipes are formulated for oat flour, but if a recipe calls for all purpose flour you can substitute oat flour for up to 25-30% the amount of regular flour in most baking recipes. Oat flour can be used to thicken gravies, soups, and stews, too.
What can I substitute for oats? Chia seeds, quinoa, and brown rice are just three oatmeal substitute options. You could also consider barley, millet, or wheat berries, all of which have certain advantages and disadvantages over oatmeal.