Ounces to Kilograms
Convert ounces (oz) to kilograms (kg). Both measure mass and weight, and the conversion comes up in cooking, shipping, fitness work.
The Formula
``
kilograms = ounces × 0.028349523125
ounces = kilograms × 35.2739619496
`
One ounce is 0.02835 kilograms, and one kilogram is 35.274 ounces.
Conversion Table
| Ounces | Kilograms |
|---|---|
| 1 oz | 0.02835 kg |
| 2 oz | 0.056699 kg |
| 5 oz | 0.141748 kg |
| 10 oz | 0.283495 kg |
| 25 oz | 0.708738 kg |
| 50 oz | 1.4175 kg |
| 100 oz | 2.835 kg |
| 500 oz | 14.1748 kg |
| 1,000 oz | 28.3495 kg |
The Other Direction
| Kilograms | Ounces |
|---|---|
| 1 kg | 35.274 oz |
| 2 kg | 70.5479 oz |
| 5 kg | 176.3698 oz |
| 10 kg | 352.7396 oz |
| 25 kg | 881.849 oz |
| 50 kg | 1,763.7 oz |
| 100 kg | 3,527.4 oz |
| 500 kg | 17,636.98 oz |
| 1,000 kg | 35,273.96 oz |
What Each Unit Is
Ounces (oz) — one sixteenth of a pound, or exactly 28.349523125 grams. From uncia, one twelfth — of the Roman libra, before avoirdupois moved it to one sixteenth.
Kilograms (kg) — defined since 2019 by fixing the Planck constant — the SI base unit of mass. Originally the mass of a litre of water, then a platinum-iridium cylinder near Paris until 2019.
A Sense of Scale
A slice of bread is about 1 oz- A tennis ball is 2 oz
- US recipes use ounces for dry goods
- A litre of water is 1 kg
- A laptop is 1.5–2 kg
- Checked baggage allowance is often 23 kg
Precision
The factor 0.028349523125 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.
Watch Out For
- A fluid ounce measures volume, not mass, and the two are only interchangeable for water by coincidence of scale.
In Code
`javascript
const ounceToKilogram = (value) => value * 0.028349523125;
``
Where This Conversion Comes Up
- Cooking
- Shipping
- Fitness
- Medicine
- Manufacturing
How Many Decimals Do You Need?
Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 oz with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 oz becomes | Error |
|---|---|---|---|
| 0 | 0 | 0 | 100.0000% |
| 1 | 0 | 0 | 100.0000% |
| 2 | 0.03 | 4.11 | 5.8219% |
| 3 | 0.028 | 3.836 | 1.2329% |
| 4 | 0.0283 | 3.8771 | 0.1747% |
The right number of significant figures is set by your input, not by the converter. If you measured ounces to three significant figures, the answer in kilograms is only good to three — writing more digits claims precision the measurement never had.