Ounce to Kilogram Converter

What is an Ounce?

An ounce (oz) is a unit of weight commonly used in the United States and a few other countries that follow the imperial system. It plays a vital role in cooking, shopping, postal services, and precious metals measurement. One ounce is approximately equal to 28.35 grams.

There are two main types of ounces:

• Avoirdupois ounce used in everyday U.S. measurements (e.g., food, mail).
• Troy ounce used to weigh precious metals like gold and silver.

The word "ounce" comes from the Latin word "uncia," meaning one-twelfth. Historically, it represented 1/12 of a Roman pound. Over time, different standards emerged, with the avoirdupois and troy systems becoming the most widely used.

• The avoirdupois system dates back to the 13th century in England.
• The Troy system was adapted from Roman coinage weight standards and became the norm for metals in the 15th century.

How Is the Ounce Used: The ounce is used in various industries and everyday tasks. Here's how it shows up in real life:

• Food and Cooking: Recipes in the U.S. often mention ingredients in ounces—like 8 oz of cheese or 2 oz of chocolate. It's a key unit for portioning and packaging.
• Mail and Shipping: The U.S. Postal Service charges based on ounces. A standard letter, for instance, must weigh 1 oz or less to qualify for a first-class stamp.
• Fitness and Nutrition: Protein powders, meat servings, and hydration levels are often measured in ounces on nutrition labels and fitness trackers.
• Jewelry and Precious Metals: Gold, silver, and platinum are measured in troy ounces, not the regular kind. One troy ounce equals about 31.1035 grams, slightly heavier than the standard ounce.

The ounce may seem like a small unit, but it’s incredibly versatile. From kitchen scales to postal counters to precious metal markets, it helps measure weight where precision matters.

What Is a Kilogram?

A kilogram, abbreviated as kg, is the standard unit of mass in the metric system used in nearly every country in the world. Whether you're weighing yourself at the gym, buying fruits at the grocery store, or measuring ingredients in a recipe, chances are you're using kilograms, especially if you're outside the U.S.

The term "kilogram" comes from French, combining kilo (meaning "a thousand") with gram. One kilogram equals 1,000 grams. Originally, the kilogram was defined by a physical object a platinum-iridium cylinder stored in France. But since 2019, scientists now define it using fundamental constants of nature like the Planck constant, making it far more precise and stable for scientific use.

How the Kilogram Is Used:The kilogram is part of everyday life in countries using the metric system:

• Health & Fitness: Body weight is typically measured in kilograms in most countries. For example, someone might say they weigh 70 kg instead of 154 lbs.
• Cooking & Groceries: Many packaged foods, fresh produce, and ingredients are labeled in kilograms or grams.
• Science & Engineering: Kilograms are used in physics, chemistry, and engineering because they're part of the SI (International System of Units).
• Global Trade: International shipping and logistics often rely on metric units for consistency.

How to Convert Ounce to Kilogram

1 oz = 0.02835 kg

Let’s say you want to convert 100 oz to kg.

Using the formula:

100 × 0.02835 = 2.835 kg

So, 100 oz is approximately 2.835 kg.

Ounce to Kilogram Conversion Table

Ounce (oz)	Kilogram (kg)
1 oz	0.028 kg
2 oz	0.057 kg
3 oz	0.085 kg
4 oz	0.113 kg
5 oz	0.142 kg
6 oz	0.17 kg
7 oz	0.198 kg
8 oz	0.227 kg
9 oz	0.255 kg
10 oz	0.283 kg
11 oz	0.312 kg
12 oz	0.34 kg
13 oz	0.369 kg
14 oz	0.397 kg
15 oz	0.425 kg

Related Conversions

• Ounce to Microgram
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• Ounce to Milligram
• Milligram to Kilogram
• Ounce to Gram
• Gram to Kilogram
• Ounce to Pound
• Pound to Kilogram
• Ounce to Stone
• Stone to Kilogram
• Ounce to US Ton
• US Ton to Kilogram
• Ounce to Imperial Ton
• Imperial Ton to Kilogram
• Ounce to Tonne
• Tonne to Kilogram