The avoirdupois ounce and the international kilogram both have exact modern definitions, making this a precise weight conversion in both directions.
How it works
Multiplying ounces by 0.028349523125 gives kilograms; dividing kilograms by that same factor gives ounces back.
What this does not include
This does not include grams or pounds directly — for those, use this site’s grams to ounces or ounces to pounds converters instead.
How to use this calculator
- Enter a value in either ounces or kilograms — the other field fills in automatically.
Frequently asked questions
Why isn’t the conversion factor a round number?
Because it derives from the exact international pound definition (453.59237 grams) divided by 16 ounces per pound — an exact but non-round result.
Is 16 oz always exactly 1 lb?
Yes — the avoirdupois ounce is defined as exactly 1/16 of a pound, so 16 oz converts to exactly 0.45359237 kg.
Where is this conversion commonly needed?
Comparing shipping weights, recipe ingredients, or product labels between countries using different weight units.
