I want to bake a cake and the recipe says i need castor sugar?

Do i have to use this or can i just use normal sugar, wil the cake come out any different? i know this is just probably common sense but ya know I want to bake a cake and the recipe says i need castor sugar?
I've done this before as I didn't have castor sugar so I just used normal white sugar and it turned out fine. The castor sugar is just meant to dissolve quicker and give the cake a bit of a lighter texture, so it doesn't make much of a difference unless your making something like a sponge cake or souffle where the texture and ingredients are important.I want to bake a cake and the recipe says i need castor sugar?
The American equivalent of castor sugar is superfine sugar. Normal sugar should work too, but if you're really worried about it, you can put your sugar in the blender and grind it a bit smaller.
Castor sugar is just sugar,so just use sugar.