How much wool to knit a child's jumper?

The amount of wool needed to knit a child's jumper typically ranges from 400 to 800 grams, depending on the size of the jumper and the thickness of the yarn. For example, a small to medium-sized jumper made with worsted weight yarn generally requires around 500 grams. It's always best to check the specific pattern for recommendations, as different designs and yarn types may alter the quantity needed.