21 pounds in ounces

Conversion

21 pounds is equivalent to 336 ounces.^[1]

Conversion formula
How to convert 21 pounds to ounces?

We know (by definition) that: $1 lb = 16 oz$

We can set up a proportion to solve for the number of ounces.

\frac{1 lb}{21 lb} = \frac{16 oz}{x oz}

Now, we cross multiply to solve for our unknown $x$ :

x oz = \frac{21 lb}{1 lb} * 16 oz \to x oz = 336 oz

Conclusion: $21 lb = 336 oz$

Conversion in the opposite direction

The inverse of the conversion factor is that 1 ounce is equal to 0.00297619047619048 times 21 pounds.

It can also be expressed as: 21 pounds is equal to $\frac{1}{0.00297619047619048}$ ounces.

Approximation

An approximate numerical result would be: twenty-one pounds is about three hundred and thirty-six ounces, or alternatively, a ounce is about zero times twenty-one pounds.

Units involved

This is how the units in this conversion are defined:

Pounds

The pound or pound-mass (abbreviations: lb, lbm for most pounds) is a unit of mass used in the imperial units, United States customary and other systems of measurement. A number of different definitions have been used, the most common today being the international avoirdupois pound which is legally defined as exactly 0.45359237 kilograms, and which is divided into 16 avoirdupois ounces.[3] The international standard symbol for the avoirdupois pound is lb.The unit is descended from the Roman libra (hence the abbreviation lb). The English word pound is cognate with, among others, German Pfund, Dutch pond, and Swedish pund. All ultimately derive from a borrowing into Proto-Germanic of the Latin expression lībra pondō a pound by weight, in which the word pondō is the ablative case of the Latin noun pondus.

Wikipedia page of pounds

Ounces

The ounce (abbreviated oz) is a unit of mass used in most British derived customary systems of measurement. It is most pervasive in the retail sale of groceries in the United States, but is also used in many other matters of domestic and international trade between imperial or customary measurement driven countries. Similar customary uses include recipes in cookbooks and sales of bulk dry goods. Whilst various definitions have been used throughout history, two remain in common use, the avoirdupois ounce equal to approximately 28.3 grams and the troy ounce of about 31.1 grams. The avoirdupois ounce is widely used as part of the United States customary and British imperial systems, but the troy ounce is now only commonly used for the mass of precious metals such as gold, silver, platinum, palladium, rhodium, etc..

Wikipedia page of ounces

Footnotes

[1] The precision is 15 significant digits (fourteen digits to the right of the decimal point).

Results may contain small errors due to the use of floating point arithmetic.

Conversion

Conversion formula How to convert 21 pounds to ounces?

Conversion in the opposite direction

Approximation

Conversion formula
How to convert 21 pounds to ounces?