Ounces to grams.
Both directions.

Fluid ounces vs weight ounces

Fluid ounces (fl oz) measure volume; weight ounces (oz) measure mass. For water, 1 fl oz ≈ 1 oz by weight (they're close but not identical — 1 fl oz of water = 29.57 g). For anything denser than water (honey, oil, cream), the weights diverge. Always check whether a recipe means fl oz or oz by context: liquids are almost always fl oz; solids like chocolate or cheese are always weight oz.

Common cooking amounts

• —1 oz chocolate = 28 g — one small square of a standard bar.
• —4 oz cream cheese = 113 g — half a standard US package.
• —6 oz chicken breast = 170 g — a typical single portion.
• —8 oz (½ lb) = 227 g — one block of most UK butter or cheese.

Avoirdupois, troy, and fluid ounces explained

Three different ounces appear in cooking and baking contexts, and mixing them up leads to significant errors. The avoirdupois ounce (28.35 g) is what virtually all cooking recipes mean when they write "oz" — it's the standard weight ounce used in the US and UK for everyday goods. The troy ounce (31.1 g) is used exclusively for precious metals and appears in no food recipe. The fluid ounce (fl oz) is a volume measure: 1 US fl oz = 29.57 ml, 1 UK fl oz = 28.41 ml. Recipes specify the context clearly — weight oz for solids, fl oz for liquids — so check before converting.

US vs UK ounce usage in recipes

US and UK recipes both use the same avoirdupois ounce (28.35 g) for weight measurements, so there is no conversion needed when moving between US and UK recipes for solid ingredients. The difference appears with fluid ounces: a US fluid ounce is 29.57 ml while a UK fluid ounce is 28.41 ml — a gap of about 4%. In practice, most modern UK recipes have switched to millilitres for liquids, so fluid ounce confusion is mainly relevant with older British cookbooks. When in doubt, weigh solids and measure liquids in millilitres to sidestep both ambiguities entirely.

Why grams eliminate measurement ambiguity

Grams are a unit of mass, not volume, which means a gram of flour is always the same amount regardless of how it's packed into a container. This is why professional bakers, pastry chefs, and cookbook developers working in the metric system prefer grams for all dry ingredients. A recipe written in grams travels perfectly across kitchens and countries — there's no packing variation, no cup-size discrepancy, and no conversion rounding. If you bake regularly from a favourite recipe, converting it to grams once and noting the values in the margin makes every future bake faster and more consistent.