⚖️ oz to kg — Ounce to Kilogram Converter

Convert weight and mass units — kilograms, pounds, ounces, grams, tons, stones.

1 unit =
From
To
Formula 1 oz = 0.0283495 kg
Quick Answer — Formula1 oz = 0.0283495 kgMultiply ounces by 0.0283495 to get kilograms.Reverse: 1 kg = 35.27399 oz
UnitNameValue
kg Kilogram 0.0283495
g Gram 28.3495
mg Milligram 28349.5
t Metric Ton 0.0000283495
lb Pound 0.0625
st Stone 0.0044642843

About Ounce to Kilogram Conversion

The Ounce (oz) and the Kilogram (kg) are both units of weight & mass. Converting between them is straightforward using the formula above.

Formula: 1 oz = 0.0283495 kg

This converter uses internationally recognized conversion factors. All calculations are performed client-side in your browser — no data is sent to any server.

Worked Examples: Ounce to Kilogram

A standard bag of flour
1 oz = 0.0283495 kg
Flour bags commonly come in 1 kg (2.2 lb) or 5 lb sizes — knowing this conversion helps when following recipes from different countries.
Adult human body weight
70 oz = 1.984465 kg
An average adult weighs about 70 kg (154 lb). Gyms and doctors in metric countries use kilograms, while US and UK individuals often quote pounds or stone.
A dumbbell pair
10 oz = 0.283495 kg
A pair of 10 kg (22 lb) dumbbells — standard gym equipment sold in metric across Europe but in pounds in the US.
A large dog
30 oz = 0.850485 kg
A medium-large dog breed (e.g., a Labrador) typically weighs about 30 kg (66 lb). Veterinary records in the UK may note both units.

Ounce to Kilogram Reference Table

Ounce (oz)Kilogram (kg)Real-world context
1 oz0.0283495 kgletter envelope
10 oz0.283495 kg
100 oz2.83495 kg
500 oz14.17475 kg
1000 oz28.3495 kg

Mental Math Tricks: Ounce to Kilogram

Divide by 35.2739907
Since the factor is small (0.0283495), it's easier to divide: kg value ÷ 35.2739907 = oz value.
Use scientific notation
1 oz = 2.83e-02 kg. Count decimal places carefully.
Think in larger units first
Convert to a more familiar unit first, then to kg.

When to Convert Ounce to Kilogram

🏋️ Fitness & Gym Gym equipment is labelled in oz in metric countries and kg in the US. Convert to understand weights when following foreign training programs.
🍳 Cooking & Baking International recipes use different weight systems. Convert Ounce ingredients to Kilogram when following recipes from different countries.
✈️ Travel & Luggage Airline baggage limits are often given in one unit while your scale shows another. Know your oz to kg conversion to avoid excess baggage fees.
🛒 Grocery Shopping Food labels switch between metric and imperial. Quickly convert oz to kg to compare prices per unit at international stores.
🏥 Medical & Health Doctors and pharmacists worldwide use different weight systems for body weight and drug dosing. Accurate conversion between oz and kg is safety-critical.
📦 Shipping & Parcels Courier services charge by weight. Knowing Ounce-to-Kilogram conversion ensures you get accurate shipping quotes when sending packages internationally.

Frequently Asked Questions — Ounce to Kilogram

1 ounce (oz) equals exactly 0.0283495 kilograms (kg). Use the formula: oz × 0.0283495 = kg.

To convert ounces to kilograms, multiply your value in ounces by 0.0283495. For example, 5 oz × 0.0283495 = 0.1417475 kg.

100 ounces = 2.83495 kilograms. Calculation: 100 × 0.0283495 = 2.83495.

To convert kilograms back to ounces, divide by 0.0283495 (or multiply by 35.2739907). Example: 10 kg ÷ 0.0283495 = 352.7399 oz.

Yes. This converter uses the internationally recognised exact conversion factor: 1 oz = 0.0283495 kg. All calculations are performed in your browser with no rounding until display.

10 ounces = 0.283495 kilograms. Simply multiply by 0.0283495.

Converting ounces to kilograms is commonly needed for everyday tasks like cooking recipes, body weight tracking, shopping internationally, or shipping parcels where one system uses oz and another uses kg.

Understanding Ounce and Kilogram

Ounce (oz)

The avoirdupois ounce (oz) equals exactly 28.349523125 grams or 1/16 of an avoirdupois pound. It is widely used in the US and UK for food portions, product packaging, and everyday measurements. Note that the troy ounce (31.1035 g), used for precious metals like gold and silver, is a different and heavier unit than the avoirdupois ounce.

Kilogram (kg)

The kilogram (kg) is the SI base unit of mass — one of seven fundamental units in the International System. Equal to exactly 1,000 grams, it is the foundation of weight measurement in science, medicine, engineering, and commerce worldwide. Uniquely among SI base units, the kilogram is named with a metric prefix ("kilo-" = 1,000).

History of the Ounce

The word "ounce" derives from Latin uncia (a twelfth), originally 1/12 of the Roman pound. The avoirdupois ounce developed in medieval England specifically for the wool trade, creating a 16-ounce pound distinct from the Troy 12-ounce pound. The British Imperial system codified the ounce in 1824. The modern exact definition (28.349523125 g) was set by the 1959 International Yard and Pound Agreement.

Interesting fact: A troy ounce (31.1 g) used for gold is heavier than an avoirdupois ounce (28.35 g) used for food — so an "ounce" of gold contains more metal than an "ounce" of flour. A standard large hen's egg weighs approximately 56–63 grams (about 2 oz).

History of the Kilogram

Defined in 1795 by the French Revolutionary government as the mass of one cubic decimetre of distilled water at 4 °C. A platinum prototype (the Kilogramme des Archives) was created in 1799. From 1889 until 2019, the world's mass standard was the International Prototype Kilogram — a platinum-iridium cylinder stored in Sèvres, France. In 2019, the kilogram was redefined in terms of Planck's constant (h = 6.626 070 15 × 10⁻³⁴ J·s), eliminating the need for a physical artifact.

Interesting fact: The IPK and its official copies drifted apart by up to 50 micrograms over 130 years, motivating the 2019 redefinition. The kilogram is the only SI unit whose name starts with a prefix.