This article is from the Cooking and Conversions FAQ, by with numerous contributions by Victor Sack cooking.faq@mac.com others.
US all-purpose flour and UK plain-flour can be substituted for one
another without adjustment. US cake flour is lighter than these. It is
not used much anymore, but if it does come up, you can substitute
all-purpose/plain flour by removing three tablespoons per cup of flour
and replacing it with corn starch or potato flour.
Self-raising flour contains 1 1/2 teaspoons baking powder and 1/2
teaspoon salt for each cup of flour. Some brands in some regions don't
contain salt.
US whole wheat flour is interchangeable with UK wholemeal flour.
 
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