How much does one gallon of sweat weigh?

The weight of sweat can vary depending on the individual and the circumstances, but on average, sweat is composed mostly of water with small amounts of electrolytes and other substances. One gallon of water weighs approximately 8.34 pounds (3.78 kilograms), so one gallon of sweat would weigh roughly the same. However, the weight of sweat can be influenced by factors such as hydration level, temperature, and physical activity.