What Is a Pound (lb)?
Definition
Pound (lb): A unit of mass used in the United States and the United Kingdom, symbol lb. Since 1959 the avoirdupois pound has been exactly 0.45359237 kilograms by definition.
The pound (symbol lb) is a unit of mass used in the United States and the United Kingdom for body weight and for goods. The everyday avoirdupois pound has been exactly 0.45359237 kilograms since the 1959 international yard and pound agreement. One pound is 16 ounces, and 14 pounds make one stone.
Where it appears in the formulas
1 lb = 0.45359237 kg, 1 oz = 1/16 lb and 1 st = 14 lb. The weight converter uses these exact definitions (NIST Handbook 44, Appendix C) and shows the value in every unit.
Not the currency, not a force
The British currency is also called the pound; the two are unrelated. The pound-force (lbf) is a unit of force; the weight converter converts only between units of mass.