Ounce to Kilogram Converter

The avoirdupois ounce is a unit of mass used in the United States and in some everyday British contexts. One avoirdupois ounce equals exactly 28.349523125 grams, or 0.028349523125 kilograms. The exact relationship follows from the international pound agreement: one pound is exactly 0.45359237 kilogram and contains 16 ounces. Dividing that kilogram value by 16 gives the ounce conversion factor used by this calculator. To convert ounces to kilograms, multiply the ounce value by 0.028349523125. Sixteen ounces become 0.45359237 kilogram, which is one international avoirdupois pound. A single ounce becomes 0.028349523125 kilogram or 28.349523125 grams. Showing both kilograms and grams helps with practical tasks because small food portions are easier to read in grams, while parcel weights and larger quantities are commonly stated in kilograms. Ounces appear on recipes, food packages, postal scales, product specifications, and shipping documents. Kilograms are the SI base unit of mass and are used by science, medicine, logistics, manufacturing, and most countries. Accurate conversion matters when adapting a recipe, checking an airline baggage limit, preparing an international shipment, comparing retail package sizes, or entering imperial measurements into a metric formula. The exact factor avoids the cumulative error that can arise from rounding one ounce to 28 or 28.35 grams too early. Not every unit called an ounce measures the same thing. A fluid ounce measures volume and cannot be converted to kilograms without knowing the substance density. A troy ounce, used for precious metals, equals approximately 31.1034768 grams and is heavier than an avoirdupois ounce. This page converts ordinary avoirdupois mass ounces only. Confirm the source unit before using the result, especially for gold, silver, medicine, liquids, or historical measurements. The calculator accepts zero and positive decimals. It displays enough fractional digits to preserve the exact factor for typical values, although the true precision of a real measurement depends on the scale used. A kitchen scale reading to the nearest ounce does not become laboratory-precise merely because the converted result has many digits. Match the final rounding to the source measurement and purpose. For shipping, follow the carrier's rounding and billing rules; for recipes, use the precision your equipment can measure; and for regulated work, retain documented units, calibration, and uncertainty.