Question: 1/2 onion equals how many cups?
Answer: Medium: A medium onion is about twice as big as a small one, weighing it at roughly 8 ounces and yielding (you guessed it) about a cup once chopped. Large: Large onions are three times larger than small onions (12 ounces), and should give you about 1 1/2 cups of chopped onion once you get at it with a knife.