The mass of a single water molecule (H2O) compared to the mass of a typical human body is like the mass of a penny compared to the mass of the Earth!

Mass and weight are related by Newton's law, *W=mg* (Weight = Mass * Gravity). The value of gravity used for these conversions is 32.1740486 ft/s² or 9.80665 m/s². The units for force (weight) and mass are based on the equations below.

**Important**: The slug is the base unit for mass in the English system, but the more common unit for mass is the Pound Mass (lbm). Under standard Earth gravity, **1 lbm weighs 1 lbf** and therefore the term "**pound**" is usually used for both mass and weight in the English system.

**MASS Conversions**

1 lbm = 0.45359237* kg (exact conversion)

1 kg = 2.2046226 lbm

1 slug = 32.1740486 lbm

1 kg = mass of 1 liter of water

1 amu = 1.66053886E-27 kg

1 metric ton = 1000 kg

**WEIGHT Conversions**

1 lbf = 4.44822 N

1 stone = 14 lbf

1 lbf = 16 oz

1 short ton (US) = 2000 lbf

1 long ton (UK) = 2240 lbf

**Mix of Mass & Weight**

1 oz = 28.349523 g

Force | = | Mass | * | Acceleration | |
---|---|---|---|---|---|

English: | 1 lbf (Pound Force) | = | 1 slug | * | 1 ft/s² |

Metric: | 1 N (Newton) | = | 1 kg (Kilogram) | * | 1 m/s² |

1 lbm = 0.45359237* kg (exact conversion)

1 kg = 2.2046226 lbm

1 slug = 32.1740486 lbm

1 kg = mass of 1 liter of water

1 amu = 1.66053886E-27 kg

1 metric ton = 1000 kg

1 lbf = 4.44822 N

1 stone = 14 lbf

1 lbf = 16 oz

1 short ton (US) = 2000 lbf

1 long ton (UK) = 2240 lbf

1 oz = 28.349523 g