Convert Pounds to kg – Are You Aware of All Facts?

pounds to kg

Kilograms and pounds are two of the most popular units of mass. While Kilogram is widely used in the world, usage of pound originates from the Imperial system and is mainly confined in the country like the United States. Given their wide uses, it would be at times essential to know how to convert pounds to kg or (lbs to kg) and vice-versa.

If you are on the go then you can roughly convert pounds to kg by multiplying pound with a factor of 0.45 or 0.5. But this won’t give you exact output and might give you an idea.


Mass (m) is a dimensionless quantity defined by the total amount of matter in a particle or object. Though kilogram is a more common unit to measure mass, the pound is also another suitable and popular unit to measure it.

The symbol for Kilogram is kg, and the symbol for pound is lbs. There are so many interesting facts about them which are fun to know. Let’s dig deeper to find them.

Conversion calculator – How to convert pounds to kg?

You can use above conversion calculator to convert pounds into kilograms. Just enter choice pound in the entry field and observe the calculated kg value.

The Formula to convert pounds to kg

1 lbs = 0.45359237 kg

You can do a rough conversion of pounds to kg by multiplying pound with a factor of 0.45 or even 0.5. But this would cause a lot of deviation and so should only be used for a very rough estimate.

The required and correct formulae for converting (M) lbs to kg would be –

M lbs = (M x 0.45359237) kg

The Formula to convert kilograms to pounds

1 kg= 2.20462262185 lbs

To do a faster calculation in your mind, you can use a factor of 2.2 to obtain an approximate value. Which means 1 kg= to 2.2 lbs. We can simplify it further by using a factor of 2 instead of 2.2.

But again don’t forget to be aware of the deviation of the approximate value from the actual one. The required and correct formulae for converting (m) kg to lbs would be –

m kg = (m x 2.20462262185) lbs

What is Pound?

The pound (which is also called pound-mass) is a unit of mass widely used in the imperial and United States customary. It is also a part of other systems of measurement. There are different kinds of definitions of pounds. But the most common definition of it is the international avoirdupois pound.

1 international avoirdupois pound = 0.45359237 kilograms

Lb is the international standard symbol for the avoirdupois pound.

There are other alternative symbols such as –

  • lbm – It is used for most of the pound definitions
  • # – It is primarily used in the U.S.
  • ℔ – It is used for the apothecaries’ pound which is a historical system of mass

The abbreviation “lb”, which we use for pound, has come from the Roman‘Libra.’ The meaning of Libra was balance or scales (as in the astrological sign also).

Another way of defining it by the ancient Roman unit of measure i.e. Libra pondo, meaning “a pound by weight.”

What is kilogram?

The kilogram or kilogramme (kg) is the base unit of mass in SI unit (International System of Units ) or the metric system.

One kilogram is equal to the mass of the International Prototype of the Kilogram (IPKor “Le Grand K” or “Big K”).

IPK is defined as a cylinder of platinum-iridium alloy stored by the International Bureau of Weights and Measures at Saint-Cloud, France.

Initially, the kilogram was defined as the mass of a liter (cubic decimeter) of water at its freezing point. But due to the inconvenience of accurately replicating the quantity, some other definition was invented.

So. in the late 18th century, a platinum artifact was taken as a standard measurement for the kilogram, and it has remained as the standard of the unit of mass for the metric system since that time.

The symbol for Kilogram is kg. A gram is equal to one-thousandth of a kilogram. The origin of the word kilogram is the French word ‘kilogramme’ whose source has in the Greek terminology, meaning “thousand.”

As stated before, the Kilogram is generally used as the unit of mass in the whole world except a few countries like the United States where the widely used unit is the pound.

Mass vs Weight (Are they the same?)

Mass and weight may seem interchangeable terms, but actually, it’s not scientifically correct at all. Mass is the measurement of the total amount of matter inside an object while weight is the measurement of the gravitational force acting on an object.


So, as you might have expected, the mass of an object is always constant, but the weight of an object may vary depending on the gravitational force of a specific place/celestial body.

For example, gravity on the moon is approximately 1/6th of the gravity on Earth. So, a man who weighs 60kg on Earth would weigh approximately 10kg on the Moon. But his mass will remain constant. Isn’t that interesting. Mass is measured by using a balance and weight is measured on a scale.

Quick lookup

Pound (lb) Kilogram (kg)
      1 lb  0.4536 kg
     2 lb  0.9072 kg
     3 lb  1.3608 kg
     4 lb  1.8144 kg
      5 lb    2.268 kg
      6 lb   2.7216 kg
      7 lb   3.1751 kg
      8 lb   3.6287 kg
      9 lb   4.0823 kg
    10 lb   4.5359 kg
  100 lb 45.3592 kg
  500 lb     226.8 kg
1000 lb   453.59 kg

Some interesting facts about pounds and kg

  1. The unit of mass was called “grave” instead of “kilogram” From 1795 to 1799.
  2. Every time the original kilogram (which is kept inside a bell jar) is measured, it is cleaned to make it dust-free for the precise measurement.
  3. The pound sterling is a currency and is entirely different from the pound.
  4. The mass & weight of a pound of feathers is equal to the mass and weight of a pound of air or water or almost anything else.
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