Convert Ounce to Kilogram (oz → kg)

Converting ounces to kilograms is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in ounces

   Start with the number of ounces (oz) you want to convert.
2. 2
   Multiply by 0.02835

   The conversion factor from oz to kg is 0.02835. Multiply your value by this number.
3. 3
   Read the result in kilograms

   The result is your value in kilograms (kg).

Multiply the value in ounces by 0.02835. For the reverse direction, multiply by 35.273962.

• ✓1 oz = 28.35 g exactly (avoirdupois); 1 troy oz = 31.10 g.
• ✓16 oz = 1 lb in the avoirdupois system used for food.
• ✓When converting a US recipe, 1 oz ≈ 2 tablespoons of a liquid ingredient.

• ✗Confusing mass ounces (28.35 g) with fluid ounces (volume).
• ✗Using avoirdupois ounces (28.35 g) for precious-metal pricing — gold is in troy ounces (31.10 g).
• ✗Multiplying lb × 16 and calling the result oz — correct only for weight, not volume.

What is the Ounce?

The ounce equals exactly 28.349523125 grams or 1/16 of a pound. The word derives from the Latin 'uncia,' meaning one twelfth (the original Roman ounce was 1/12 of a Roman pound). The modern avoirdupois ounce, used for everyday weights in the United States and the United Kingdom, replaced the older Tower and Troy systems. It is the standard unit for American kitchen recipes (where 'ounce' refers to weight, distinct from the fluid ounce of volume), postal rates, package sizes (a 12-oz can of soda), and boxing-glove weights. Precious metals like gold and silver use the troy ounce (31.103 g), about 10% heavier than the avoirdupois ounce. The ounce relates to the pound (16 oz = 1 lb), the gram (1 oz ≈ 28.35 g), and the grain (1 oz = 437.5 grains).

• American and British cooking recipes
• Food packaging in the US
• Precious metals (troy ounce = 31.10 g, different from avoirdupois)

What is the Kilogram?

The kilogram is the base SI unit of mass. Since May 2019, it has been defined by fixing the numerical value of Planck's constant to exactly 6.62607015 × 10⁻³⁴ joule-seconds — a major shift from the previous definition based on a physical platinum-iridium artifact (the International Prototype Kilogram or 'Le Grand K') stored at the BIPM near Paris since 1889. This redefinition links the kilogram to a fundamental constant of nature, making it reproducible by any sufficiently equipped laboratory. The kilogram is the global standard for body weight (most countries quote weight in kilograms), grocery sales, scientific measurements, and engineering. One liter of pure water at 4°C has a mass of almost exactly 1 kg — a coincidence designed into the original 1795 definition. The kilogram relates to the gram (1,000 g = 1 kg), the metric ton (1,000 kg = 1 t), and the pound (1 kg ≈ 2.205 lb).

• Human body weight in most of the world
• Grocery and retail food quantities in Europe
• Scientific and engineering mass measurements