Cups to Milliliters Converter

Converting cups to millilitres depends on whose cup is meant, and this is the least standardised of all the common cooking measures. The US customary cup used here is 236.5882 millilitres. The metric cup used in Australia, New Zealand and Canada is a round 250 millilitres. The traditional UK cup was around 284 millilitres, though modern British recipes generally use weights instead. A recipe calling for a cup can therefore mean anything across a twenty per cent range.

For most cooking this variation is tolerable — a soup or a stew absorbs it without complaint. For baking it is not, because the ratios between flour, liquid, and leavening determine structure. A cake made with metric cups from a recipe written for US cups receives about six per cent more of everything, which alone is survivable, but the error compounds if some ingredients are converted and others are not.

The deeper problem with cups is not which cup but the measure itself. A cup measures volume, and dry ingredients pack to wildly different densities depending on how they are handled. Flour scooped directly from the bag can weigh twenty per cent more than flour spooned in and levelled, because scooping compacts it. That variation dwarfs the difference between cup standards, and it is why the same recipe can produce different results in different hands even with identical ingredients.

The reliable answer is to weigh. Professional and serious amateur baking recipes specify grams precisely because mass does not vary with technique. Where a recipe gives only cups, converting to grams using a per-ingredient density is more reliable than measuring volume, but the density figure has to match the ingredient — flour, sugar, and butter all differ substantially.