Converting Ounces to Grams

It's helpful to know how to convert ounces to grams for recipes and lab experiments. Many products labeled in ounces list the number of grams.
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This worked example problem demonstrates how to convert ounces to grams. This is a common type of mass unit conversion problem. One of the most common practical reasons to know how to do this conversion is for recipes, so let's start with a food example:

Ounces To Grams Problem

A chocolate bar weighs 12 ounces. What is its weight in grams?


One of the easiest ways to solve this problem is to use the pound to kilogram conversion. If you like in a country where both units are used, this is a useful conversion to know. Start by converting ounces into pounds. Then convert the pounds into kilograms. All that remains is to move the decimal point three places to the right to convert kilograms into grams.

Here are the conversions you need to know:
16 oz = 1 lb
1 kg = 2.2 lbs
1000 g = 1 kg
You are solving for "x" numbers of grams. First, convert ounces into pounds. The next part of the solution converts pounds to kilograms, while the final section converts kilograms to grams. Note how units cancel each other out, so all you are left with is grams.

x g = 12 oz
x g = 12 oz x (1 lb/16 oz) x (1 kg/2.2 lb) x (1000 g/1 kg)
x g = 340.1 g


The 12 oz chocolate bar weighs 340.1 g.

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Your Citation
Helmenstine, Anne Marie, Ph.D. "Converting Ounces to Grams." ThoughtCo, Aug. 25, 2020, Helmenstine, Anne Marie, Ph.D. (2020, August 25). Converting Ounces to Grams. Retrieved from Helmenstine, Anne Marie, Ph.D. "Converting Ounces to Grams." ThoughtCo. (accessed June 7, 2023).