Making your own self-rising flour

I have a recipe that calls for SR flour. I thought to use plain and add baking power, but the recipe calls for me to add that too! So, what should I do? THe recipe says I need:

250g sr flour
1tsp baking powder

If I use plain, I don't want to add too much/less powder than I should.

Thanks!

Self raising flour is nothing more mysterious than plain flour with baking powder in it. What's the recipe you're using? Normally just adding a teaspoon or two of baking powder works fine, add more if you want the thing to expand more, less if you want it more solid. Usually most recipes don't need precise amounts so guesswork will be just fine.

The recipe is for chocolate mocha muffins. I was going to use plain flour and add baking powder, but then saw it wanted me to add a tsp anyway! Now, I don't know how much to use.

For 1 cup and 2 tbsp of plain flour, you need half a teaspoon of baking powder.

Apparently there are 229.92 grams per cup (thanks Google) so it's probably a cup and a bit.

Just lob in half a teaspoon to make it into self-raising, then add the extra teaspoon that the recipe wants you to add.

One cup self-rising flour equals:
1 cup all-purpose flour, plus
1 1/4 teaspoons baking powder, plus
1/8 teaspoons salt.

Just mix up two cups and use what you need

Great, thank you guys!

I have an old cutting from a womans magazine in the UK. a lady from the UK living abroad asked how she could make SR flour. The cookery editor answered, add 2 and a half level teaspoons of baking powder to every 8oz(200g) of plain flour. I haven,t tried this yet but I will be soon. I hope this is useful to everyone.