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Ounces to kilograms

Multiply ounces by 0.0283495 to get kilograms.

1 oz = 0.0283495 kgNIST HB 44 · BIPM SI
oz
0.56699kg

20 oz = 0.56699 kg

How to convert ounces to kilograms

The kilogram is the SI base unit of mass, fixed since 2019 by defining the Planck constant as exactly 6.62607015×10⁻³⁴ J·s. The ounce is one sixteenth of an avoirdupois pound, exactly 28.349523125 grams.

Worked example — 20 oz: 20 × 0.0283495 = 0.56699 kg.

Ounces to kilograms table

Common conversions. The reverse table is on kilograms to ounces.
OuncesKilograms
1 oz0.0283495 kg
5 oz0.141748 kg
10 oz0.283495 kg
16 oz0.453592 kg
20 oz0.56699 kg
35 oz0.992233 kg
50 oz1.4175 kg
100 oz2.835 kg
160 oz4.5359 kg

Reverse and related

About ounces and kilograms

Ounce (oz)

1 oz = 0.0283495 kg

Definition. One sixteenth of an avoirdupois pound, exactly 28.349523125 grams

History and origin

The ounce comes from the Roman uncia, a twelfth of the libra; the modern avoirdupois ounce is instead one sixteenth of the pound. Through the 1959 agreement it works out to exactly 28.349523125 grams.

Current use

Ounces are used in the United States for food portions, packaged goods and letter mail, and worldwide for boxing weights and some recipes.

Source: NIST Handbook 44, Appendix C §5 (Tables of Equivalents)

Kilogram (kg)

1 kg = 35.274 oz

Definition. The SI base unit of mass, fixed since 2019 by defining the Planck constant as exactly 6.62607015×10⁻³⁴ J·s

History and origin

The kilogram began in 1795 as the mass of one litre of water at the melting point of ice, and from 1889 was embodied in a platinum-iridium cylinder kept near Paris, the International Prototype Kilogram. In 2019 the SI retired that physical artefact and redefined the unit through a fixed value of the Planck constant, leaving its size unchanged.

Current use

It is the base unit of mass almost everywhere on Earth. The main everyday exception is the United States, where people weigh in pounds even though US science, medicine and industry work in kilograms.

Source: BIPM, The International System of Units (SI), 9th ed. (2019)

Where people use this

Ounces: recipe portions, letter mail, packaged food. Kilograms: body weight outside the US, groceries and produce, checked-luggage limits. About 35.3 oz make 1 kg.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 kg = 35.27396195 oz, so 1 oz = 1 ÷ 35.27396195 = 0.0283495 kg.

Every value is carried to full double precision; the display is rounded.

Sources: BIPM, The International System of Units (SI), 9th ed. (2019); NIST Handbook 44, Appendix C §5 (Tables of Equivalents).

Questions people ask

How many ounces make a kilogram?

About 35.3 ounces make one kilogram. To convert ounces to kg, divide by 35.274.

How many kg is 16 oz?

16 ounces, which is one pound, is about 0.454 kg.

What is 32 oz in kg?

32 ounces is about 0.907 kg.

All ounce conversions