Common kitchen conversions, with worked examples

Conversion charts are useful only if you can check them, so this guide works every example out in full. The method is always the same: millilitres = grams ÷ density, and grams = millilitres × density. A US cup is 236.6 millilitres throughout. All results are approximate, because density varies by brand and packing, but the method is exact, so you can repeat it for any amount.

Start with water, the easy case. Water has a density of 1.00 grams per millilitre, so 250 grams of water is 250 millilitres, which is just over one US cup (250 ÷ 236.6 = 1.06 cups). This is the only ingredient where grams and millilitres can be swapped freely, and it is the reason so many people assume the swap works everywhere. It does not.

All-purpose flour, at 0.53 grams per millilitre, is the most important example for bakers. Two hundred grams of flour is 200 ÷ 0.53 = 377 millilitres, or 377 ÷ 236.6 = 1.59 cups — about one and a half cups plus a tablespoon. Going the other way, one US cup of flour is 236.6 × 0.53 = 125 grams. If your recipe says one cup and you only have a scale, 125 grams is the number to use, and you now know where it came from.

Granulated sugar, at 0.85 grams per millilitre, packs more densely. Two hundred grams of sugar is 200 ÷ 0.85 = 235 millilitres, which is almost exactly one US cup. That coincidence is handy, but do not generalise from it: 200 grams of flour and 200 grams of sugar are different volumes, and swapping them cup for cup would change a recipe noticeably.

Butter, at 0.96 grams per millilitre, is close to water. One hundred grams of butter is 100 ÷ 0.96 = 104 millilitres, and one US cup is 236.6 × 0.96 = 227 grams. In many countries butter is sold in 250-gram blocks, so half a block is 125 grams, or about 130 millilitres — a useful number when a recipe calls for half a cup of melted butter and you would rather weigh it.

Honey, at 1.42 grams per millilitre, shows the other extreme. One hundred grams of honey is 100 ÷ 1.42 = 70 millilitres, less than a third of a cup. A recipe that calls for a cup of honey is asking for about 336 grams — far heavier than a cup of anything else on this page. Measuring honey by weight is also simply easier, because it sticks to cups and spoons.

Milk, at 1.03 grams per millilitre, and cooking oil, at 0.91, sit near water. Two hundred and fifty millilitres of milk weighs about 258 grams; the same volume of oil weighs about 215 grams. For most cooking, the difference between milk and water by weight is small enough to ignore, but in baking, where ratios matter, it is worth knowing.

A final habit will save more recipes than any chart: when a recipe gives you a choice, weigh dry ingredients and measure liquids by volume. That matches how each kind of ingredient behaves, and it keeps the two kinds of error — packing for solids, reading a meniscus for liquids — as small as possible. And when you convert, write the density next to your answer. Future you will be glad past you did.

Convert your own amounts with the kitchen converter, and read why grams and millilitres are not the same thing if the idea is new to you.