Courses for Kids
Free study material
Offline Centres
Store Icon


Reviewed by:
Last updated date: 21st Jul 2024
Total views: 184.2k
Views today: 5.84k
hightlight icon
highlight icon
highlight icon
share icon
copy icon

Ounce - Definition and Conversion

Suppose you are planning to make several dozen almond cookies for a bake sale. You are going to make it with the help of a recipe and the recipe mentioned two pounds of almonds. Now the problem is that when you go to the shop you come to know that shopkeepers sell almonds in an ounce. So, the first question that arises in your mind is “what is an Ounce”. An ounce is the smallest unit of weight measurement. On most of the packages, it is abbreviated as “oz” which comes from the Italian and Spanish word onza. An ounce weight is approximately equal to a slice of bread.

In this article we will learn the basic measurement system ounce in detail along with conversion of the units and a few solved examples. Let’s start with the history of the “Ounce: a unit of weight”.

History of Ounce

Basically, the word ounce came into the English dictionary from Anglo-Norman French, and there it is mentioned as “Unce or Ounce”.But its abbreviation is taken from medieval history where it is mentioned as “onza”. Both Mass and Weight can be measured in ounces and grams. In the United States of America, ounces are used to measure the mass and weight because it is $\dfrac{1}{16}^{th}$ part of a pound.

The units of measurement associated with the ideas of mass and weight are grammes and ounces. The gramme is a metric unit of mass measurement. Using the right conversion factors, we may convert grams to any of these ounces. Multiply the gramme value by 0.035 ounces per gramme to get the ounces per gramme value. This will give you ounces in the United States. We can claim that 100 grams equals 3.5 ounces as an example.

One Ounce is Equal to How Many Grams?

We know that an ounce is a unit of weight and mass. Since grams or pounds both are also the units of weight we can convert ounces into grams or pounds depending upon our convenience. We can do the conversion of ounces using unit conversion methods.

For many years people used the unit of an ounce without any standardized value and once they knew the importance of it then they defined it. According to the imperial system one ounce can be defined as $\dfrac{1}{16}^{th}$ of a pound (lb) and in the avoirdupois system ounce is represented by oz. Here lb is the unit of a pound.

It can be written in the mathematical form as,

$1~oz=\dfrac{1}{16}^{th}\times1~lb$ ………....(1)

Now if we multiplied the above relation by 32 then we get to know that,


Therefore, we came to know that thirty-two ounces are equal to two pounds.

Now, let’s convert lbs into kilograms (kg) to get the value of an ounce into kgs. As we know that 1 lb = 0.4535 kg. Upon putting this value in the equation (1) we get,


We can write the above equation in grams as,

$1~oz=0.02834\times1000 ~g=28.34 ~g$ (Because 1 kg = 1000 g)

Hence, one ounce contains 28.34 g weight.

Therefore, we get the following conversions of an ounce into various units of weight:

$32~oz=2~lb$(Conversion of ounce into pound)

$1~oz =0.02834 ~kg$ (Conversion of ounce into kilogram)

$1~oz =28.34 ~g$ (Conversion of ounce into grams)

Conversion Problems on Ounce

1. 40 g is equal to how much an ounce?

Ans: As we know that $1~oz =28.34 ~g$. Therefore, we are going to use this relation to solve this problem. We can also write the relation as,

$28.34 ~g=1 ~oz $

So, $1~g=\dfrac{1}{28.34}~oz$

Therefore upon multiplying the above relation by 40 we can get the answer to our problem.


Hence, 40 g of a quantity is equal to 1.411 oz.

2. Convert 1.5 kg to ounces.

Ans: Using the relation 1 oz = 0.02834 kg. We can tackle this problem. The same relation can be written as,

$0.02834 ~kg=1 ~oz $

So, $1~kg=\dfrac{1}{0.02834}~oz$

Upon multiplying the above relation with 1 kg we get,


Therefore, 1.5 kg is equivalent to 52.92 oz.

Interesting Facts

In North America, Asia, and the United Kingdom, ounces are also used to describe the "weight," or more precisely the areal density, of a textile fabric, as in "16 oz denim." The number denotes the weight in ounces of a specified amount of fabric, such as a yard of a specific width or a square yard, where the fabric's depth is a fabric-specific constant.


The ounce is the name given to a number of various mass, weight, and volume units that are derived practically intact from the uncia, an Ancient Roman unit of measurement. In the United States, the ounce is still the standard unit of measurement.

Competitive Exams after 12th Science

FAQs on Ounce

1. What does per ounce mean and what is an ounce unit?

An ounce is the unit of measurement for weight and mass. By the term “per ounce” we mean that it is the $\dfrac{1}{16}^{th}$  part of a pound and one pound is equal to 0.4535 kg. Hence, one ounce is equal to 0.02834 kg. From medieval history, people used the unit of an ounce as “oz” and it is one of the frequently used units for the measurement of weight in the United States of America.

2. What should be the conversion rate between grams and ounces? 

To find the conversion rate between grams and ounces we will use the relation 

1 oz = 28.34 g. 

We can also write the relation as,

$28.34 ~g=1 ~oz $

By dividing the above equation by 28.34g we can write 1 g in ounce as,


Upon division we get,

$1 ~g=0.0352 ~oz $

Hence, the above relation gives the relation of the conversion rate between grams and ounces.

3. What are the differences between one fluid ounce and one ounce?

The main distinction between them is that a fluid ounce is used to measure fluid substances whereas an ounce is used to measure solid substances. A fluid ounce is represented by “fl oz” while an ounce is denoted by “oz”.Moreover, the fluid ounce is a unit of measurement for the volume occupied by a liquid. A fluid ounce is commonly used to measure the volume of wines, beverages, and other liquids whereas an ounce is used to measure the weight of packages, fabrics, and papers. In today’s world, fluid ounces are measured using two different systems. The imperial fluid ounce and the US customary fluid ounce are the two measurements.1/160th of an imperial gallon is equal to an imperial fluid ounce.1/40th of an imperial quart and 1/10th of an imperial cup are also equivalent. 

4. What is an ounce used to measure?

One ounce is defined as 1/16th of a pound (lb) in the imperial system, while an ounce is represented as oz in the avoirdupois system. The ounce is a weight measurement unit. This measurement is most commonly used for dry ingredients like flour or sugar, although it can also be used for honey or yogurt. When a recipe calls for ounces, it's a measurement of weight. You'll note that baking instructions are written in ounces rather than cups since measuring ingredients by weight is more precise. A scale is the most accurate way to measure ounces.