The pound abbreviated as "lb" is a unit of mass that is commonly used in the United States. But the International System of Units, or the metric system, defines the kilogram as a unit of mass. In addition, grams and tons often express weights in the metric system, as well. Use a calculator to convert the mass in pounds to the metric system units.

Multiply the weight in pounds by 0.4536 to convert it to kilograms. For example, 23 pounds will be converted to 23 x 0.4536 = 10.4328 kilograms.

Multiply the weight by 453.5924 to convert pounds to grams. For instance, the weight of 2.3 pounds corresponds to 2.3 x 453.5924 = 1,043.2625 grams.

Multiply the weight by 0.00045359 to convert pounds to tons. For instance, the weight of 5,675 pounds is converted as to 5,675 x 0.00045359 = 2.5741 tons.