Ounces to Kilograms (oz to kg)

How to convert ounces to kilograms

Multiply the ounces by 0.028349523125:

kg = oz × 0.028349523125

8 oz × 0.0283495 = 0.2268 kg. The factor is exact by definition: an avoirdupois ounce is 1/16 of a pound, and the pound is defined as 0.45359237 kg. Dividing by 35.274 gives the same answer, since one kilogram is 35.274 ounces. To go the other way, see ounces to grams or kg to lbs.

For a quick estimate, 35 ounces is about a kilogram and 3.5 ounces about 100 grams. So a 12 oz package is a little over a third of a kilogram (0.34 kg), a 5 oz can of tuna is 0.14 kg, and a 32 oz (2 lb) bag of rice is 0.91 kg.

Ounces to kilograms chart

Pounds and ounces together

Many weights in the U.S. are written as pounds and ounces — a newborn of 7 lb 8 oz, a parcel of 2 lb 5 oz. Convert the pounds and the ounces separately and add: 7 lb is 3.175 kg and 8 oz is 0.227 kg, so the baby weighs 3.40 kg. Or turn everything into ounces first: 7 × 16 + 8 = 120 oz, and 120 × 0.02835 = 3.40 kg. For whole pounds, lbs to kg is quicker; to split a pound value into pounds and ounces, see oz to lbs.

Packages, food and shipping

Food labels in the U.S. list net weight in ounces with grams beside it, and shipping rates are often set by the ounce up to a pound and by the pound above that. International carriers and customs forms ask for kilograms, so a 28 oz parcel goes on the form as 0.79 kg. Carriers usually round weight up, so check whether your form wants the exact value or the next whole kilogram.

Fluid ounces and troy ounces

The ounce on a kitchen scale is a unit of weight. A fluid ounce on a bottle is a unit of volume, 29.57 mL, and converts to kilograms only through the density of the liquid — for water, 1 fl oz weighs about 29.6 g, close to an ounce but not the same. Gold, silver and platinum are priced in troy ounces of 31.1035 g, about 10% more than the ordinary 28.35 g ounce, so 10 troy ounces of silver weigh 0.311 kg.