Convert ounces to grams

One ounce is 28.3495231 grams. To convert any amount, multiply by 28.3495231. Going the other way, one gram is 0.0352739619 ounces.

Multiply the ounce figure by 28.3495231. So g = oz × 28.3495231. For a quick mental estimate, multiplying by about 28.3 gets you within a percent or so, which is close enough for most everyday purposes.

One ounce is about the mass of a slice of bread. The avoirdupois ounce is one sixteenth of a pound. It is distinct from the fluid ounce, which measures volume, and from the troy ounce used for precious metals.

One gram is about the mass of a paperclip. The gram is the unit of nutrition labels and recipes worldwide, and of postal rates in most of the metric world.

No, and the difference matters. The avoirdupois ounce here measures mass — one sixteenth of a pound, about 28.35 grams. A fluid ounce measures volume, about 29.6 mL in the US. They only coincide for water by rough accident, so substituting one for the other in a recipe will be wrong for anything denser or lighter. There is also the troy ounce, about 31.1 grams, used for precious metals.

Yes. Since the 1959 international yard and pound agreement, the imperial and metric systems are related by exact definitions rather than measurements — the inch is exactly 25.4 mm and the pound exactly 0.45359237 kg. Everything derived from those, including this conversion, is therefore exact. Round at the end rather than partway through, since rounding oz before converting introduces an error the conversion then multiplies.