Neither is universally better; rather, it depends on what you're washing. Liquid detergent is a great choice for everyday loads and greasy stains because it dissolves quickly, even in cold water. Powder detergent often works well on heavily soiled laundry and can be a more economical option for large households. If you want a gentler, luxury option, though, plant-based and fragrant detergents often come in the liquid form.