# Convert lbs to kg

Please provide values below to convert pound [lbs] to kilogram [kg], or *vice versa*.

### Pound

**Definition:** A pound (symbol: lb) is a unit of mass used in the imperial and US customary systems of measurement. The international avoirdupois pound (the common pound used today) is defined as exactly 0.45359237 kilograms. The avoirdupois pound is equivalent to 16 avoirdupois ounces.

**History/origin:** The pound descended from the Roman libra, and numerous different definitions of the pound were used throughout history prior to the international avoirdupois pound that is widely used today. The avoirdupois system is a system that was commonly used in the 13^{th} century. It was updated to its current form in 1959. It is a system that was based on a physical standardized pound that used a prototype weight. This prototype weight could be divided into 16 ounces, a number that had three even divisors (8, 4, 2). This convenience could be the reason that the system was more popular than other systems of the time that used 10, 12, or 15 subdivisions.

**Current use:** The pound as a unit of weight is widely used in the United States, often for measuring body weight. Many versions of the pound existed in the past in the United Kingdom (UK), and although the UK largely uses the International System of Units, pounds are still used within certain contexts, such as labelling of packaged foods (by law the metric values must also be displayed). The UK also often uses both pounds and stones when describing body weight, where a stone is comprised of 14 pounds.

### Kilogram

**Definition:** A kilogram (symbol: kg) is the base unit of mass in the International System of Units (SI). It is currently defined as being equal to the mass of the International Prototype of the Kilogram (IPK), a cylinder made of a platinum-iridium alloy.

**History/origin:** The name kilogram was derived from the French "kilogramme," which in turn came from adding Greek terminology meaning "a thousand," before the Late Latin term "gramma" meaning "a small weight."

Unlike the other SI base units, the kilogram is the only SI base unit with an SI prefix. SI is a system based on the meter-kilogram-second system of units rather than a centimeter-gram-second system. This is at least in part due to the inconsistencies and lack of coherence that can arise through use of centimeter-gram-second systems, such as those between the systems of electrostatic and electromagnetic units.

The kilogram was originally defined as the mass of one liter of water at its freezing point in 1794, but was eventually re-defined, since measuring the mass of a volume of water was imprecise and cumbersome. The current definition of a kilogram, defined as being equal to the mass of a physical prototype, is still imperfect. This is evidenced by the fact that the mass of the original prototype for the kilogram now weighs 50 micrograms less than other copies of the standard kilogram.

**Current use:** As a base unit of SI, the kilogram is used globally in all fields and applications, with the exception of countries like the United States, where the kilogram is used in many areas, at least to some extent (such as science, industry, government, and the military) but typically not in everyday applications.

**Possible future changes:** The definition of some SI base units may change in the near future. The International Committee for Weights and Measures (CIPM) has proposed re-definition of some of the SI base units in an attempt to further improve the system. Although the definitions of some units may change, the actual size of the units would remain the same; the change in definition will not have much, if any, effect on the daily use of these units.

The kilogram is one of the SI units being considered for re-definition. The current definition is based on the mass of a physical prototype which has been seen to change over time. Although the measured change is relatively small (50 micrograms), having a standard of measurement that changes at all is undesirable. As such, the proposed re-definition of the kilogram seeks to make the kilogram a measurement based on a constant of nature, rather than a physical standard that is subject to change.

If the formal vote to change the definition passes, the kilogram will instead be based on Planck's constant. This change would tie the definition of the kilogram to that of the second and the meter. Even though this would change the definition of the kilogram, the actual size of the unit will remain the same. The proposed changes are intended to improve the definitions of SI base units, not to actually change how the units are used throughout the world.

### Pound to Kilogram Conversion Table

Pound [lbs] | Kilogram [kg] |
---|---|

0.01 lbs | 0.0045359237 kg |

0.1 lbs | 0.045359237 kg |

1 lbs | 0.45359237 kg |

2 lbs | 0.90718474 kg |

3 lbs | 1.36077711 kg |

5 lbs | 2.26796185 kg |

10 lbs | 4.5359237 kg |

20 lbs | 9.0718474 kg |

50 lbs | 22.6796185 kg |

100 lbs | 45.359237 kg |

1000 lbs | 453.59237 kg |

### How to Convert Pound to Kilogram

1 lbs = 0.45359237 kg

1 kg = 2.2046226218 lbs

**Example:** convert 15 lbs to kg:

15 lbs = 15 × 0.45359237 kg = 6.80388555 kg