Ounces to Grams Converter

Converting ounces to grams means multiplying by 28.349523125. The factor is exact, following from the international definition of the pound as 0.45359237 kilograms divided into sixteen ounces. For everyday cooking, rounding to 28.35 or even 28 introduces error small enough not to matter for most dishes, though baking is less forgiving.

The practical structure of imperial recipe quantities is worth understanding. Ounces run to sixteen before rolling over into a pound, so recipes tend to use fractions of that: 4 oz is a quarter pound at about 113 g, 8 oz is a half pound at about 227 g, and 16 oz is a full pound at 453.6 g. Those quarter-pound steps are why the table on this page steps through them rather than using round metric numbers.

The critical distinction, as with the reverse conversion, is between ounces of mass and fluid ounces of volume. Recipes frequently use both, sometimes on the same line, and the abbreviation is often just 'oz' for either. Eight ounces of chocolate is a mass; eight fluid ounces of milk is a volume, and they convert to entirely different metric quantities — about 227 g versus about 237 ml. Reading which is meant from context is a necessary skill when working across recipe traditions.

A further complication is that the US and imperial fluid ounces differ slightly, at about 29.57 ml and 28.41 ml respectively, so British and American recipes using fluid ounces are not perfectly interchangeable either. For mass, though, the ounce is the same in both systems, which makes this particular conversion one of the more dependable ones in cooking.