SpriteBatch.DrawString, Draw Calls

How many Draw calls does DrawString need?

I made my own font system which Draws strings from a spritesheet, I think I need 1 Draw call per character, because I’m picking the character from the spritesheet and drawing it (correct me if I’m wrong).

I measured the execution time of DrawString, and my own function, they are pretty much even. Some frames my function is faster and some frames DrawString is faster but really small difference.