How this calculator works
A cup measures volume and a gram measures mass, so the conversion depends on what is in the cup. The table in this calculator uses the household measures published in USDA FoodData Central for one US customary cup of 236.588 mL. Flours are the most variable: sifting, spooning and scooping the same flour can change the weight of a cup by 20 per cent or more. Weighing is the only way to be exact, but a cup weight is close enough for most cooking.
Formula
grams = cups x grams per cup. cups = grams / grams per cup. grams per cup = density in grams per millilitre x 236.588. The calculator uses 125 g per cup for all-purpose flour, 200 g for granulated sugar, 227 g for butter and 236.6 g for water.
Worked example
The recipe wants 250 g of all-purpose flour. At 125 g per US cup, 250 / 125 = 2 cups. The same 250 g of granulated sugar is 250 / 200 = 1.25 cups, and 250 g of honey is 250 / 339 = 0.7375 cups, because honey is much denser than flour.
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Frequently asked questions
Why do different sites give different grams per cup for flour?
They assume different filling methods. A spooned and levelled cup of all-purpose flour is about 125 g, while a scoop straight from the bag can hold 140 g or more. The USDA household measure used here is 125 g. If your recipe came with a tested cup weight, use that figure as a custom density.
Should I use a US cup or a metric cup?
The calculator defaults to the US customary cup of 236.588 mL. Canadian and Australian recipes sometimes use a 250 mL metric cup, which is about 5.7 per cent larger. When the recipe uses one, enter the volume in millilitres instead, so a metric cup is 250 mL.
Can I convert any ingredient?
Yes, if you know its density. Choose Custom ingredient and enter grams per millilitre, for example 1.03 for whole milk. Values for very chunky foods, such as chopped nuts or cereal, depend heavily on how they settle in the cup, so treat those results as estimates.
Is a cup of water exactly 236.6 g?
Very nearly. Water at room temperature is about 0.998 g/mL, and the USDA household measure for a cup of water is 236.6 g. For cooking purposes the difference from 1 g/mL is negligible.