How much bicarb do you add to plain flour to make it self raising?

Self-raising flour is just plain flour with a pinch of baking soda. To make your own self-raising flour, add 1 teaspoon of baking soda for every 225g plain flour.

Self-rising flour is a mixture of all-purpose flour and baking powder. To make your own, add 1 1/2 teaspoons of baking powder to every cup of flour.

To make self raising flour, add 1 1/2 teaspoons of baking powder and 1/2 teaspoon of salt for every cup of plain flour.