The stone is a unit of weight measurement primarily used in the United Kingdom and Ireland. It measures a quantity of mass, specifically equating to 14 pounds or approximately 6.35 kilograms. The symbol for stone is st. This unit is standard in everyday usage, especially for personal body weight. For example, a person might say they weigh "nine stone and ten pounds." Beyond casual use, the stone remains important in various practical and scientific contexts, offering a unique perspective on mass that differs from the metric system commonly used worldwide. Despite the global trend toward metrication, the stone endures as a traditional and culturally significant unit of measurement in regions where it is utilized.