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Convert oz to kg
1 oz = 0.028349523125 kg
Type a value in ounces and the answer in kilograms appears as you go. The conversion is exactly 0.028349523125 kg to the ounce, and it happens on your own machine — this page asks nothing of a server once it has loaded.
Where it runs
In your browser. The number you type is never part of a request.
Exact by definition
1 oz is exactly 0.028349523125 kg — a definition, not a rounded factor.
Answers as you type
No button, no wait. The worked answer is already on the page before any script runs.
Ounce and Kilogram
An ounce is a sixteenth of a pound. It is not the fluid ounce, which measures volume, and the two are only loosely related — a fluid ounce of water weighs about an ounce, which is where the name came from and where the confusion starts.
The kilogram was the last unit defined by a physical object — a cylinder in a vault near Paris that was slowly losing mass. Since 2019 it has been fixed to the Planck constant instead.
ounces to kilograms in practice
16 oz is 0.4536 kg
— a pound of flour.
8 oz is 0.2268 kg
— half a pound.
ounces to kilograms at a glance
| oz | kg |
|---|---|
| 1 | 0.028349523125 |
| 2 | 0.05669904625 |
| 3 | 0.085048569375 |
| 5 | 0.141747615625 |
| 10 | 0.28349523125 |
| 20 | 0.5669904625 |
| 50 | 1.41747615625 |
| 100 | 2.8349523125 |
Every figure here is computed from the same definition the calculator uses, so the table cannot drift away from the answer above it.
Convert oz to kg: common questions
How many kilograms are in a ounce?
Exactly 0.028349523125. One ounce is 0.028349523125 kilograms, and the box above will do it for any figure you type.
Is this conversion exact, or rounded?
The ratio is exact. It is not a rounded constant typed into a table: it is derived from the definitions of the two units, so it agrees with any other correct converter to as many digits as you care to compare.
Why does another converter show a slightly different number?
Almost always rounding rather than disagreement. Many converters cut the answer to two or four decimals, and some carry a factor that was rounded before the multiplication rather than after. The figures here are computed from the exact definitions and only rounded on the way to the screen.
Where these figures come from
The claims this page makes about weight units are checkable, and these are the documents that settle them.
How this page works
The factor is a constant in the page and the arithmetic is four operations, so nothing is sent anywhere and nothing needs to be. The number you type never leaves the browser — there is no request for it to travel in.