Cooking conversions

For liquids, the safest conversions are the ones with a fixed definition. One millilitre converts to 0.033814 US fluid ounces, so 250 ml is 8.4535 US fluid ounces, and 500 ml is 16.9070 US fluid ounces. One litre is 0.264172 US gallons, so a 2-litre jug is 0.528344 US gallons. Use the converter on the home page for the exact figure, and use the automatic reverse check to confirm it returns to your starting amount.

Cups are not universal

Cups need more care than millilitres, because a cup is not a single universal size. A metric cup as used in Australia is 250 ml, while a US customary cup is about 236.6 ml and is often rounded to 240 ml in recipes. That difference is small in one cup but adds up across a whole recipe, so check where the recipe comes from before you convert cups to millilitres. If a recipe only gives cups and you need precision, for example in baking, weigh the ingredient or use a metric jug rather than converting cup by cup.

Weigh dry ingredients

Weight in cooking is more reliable than volume for dry ingredients: one ounce is 28.3495 grams, so 8 ounces is 226.796 grams. Volume and weight are not interchangeable unless you know the ingredient's density, so do not convert grams to millilitres with a single factor. Convert like to like — volume to volume, weight to weight — and the results will stay consistent.