What is the weight of water per liter in kilograms?

Water has a well-established density of approximately 1 kilogram per liter at standard temperature and pressure. This means that for every liter of water, the mass is equivalent to 1 kilogram. This property of water is essential in various fields, including nutrition, exercise science, and body composition assessment, as it serves as a fundamental benchmark for measurements involving fluids. Understanding this characteristic is crucial when considering hydration status and fluid intake recommendations for individuals involved in fitness and health-related activities.