Grams to cups:
converting sugar by weight into cups

Why one conversion figure cannot cover every sugar

Recipes written in cups and recipes written in grams describe the same sugar in two different ways, and the bridge between them is density. A cup holds a fixed volume of 236.6 millilitres, but the weight that fits into that volume changes with the size of the crystals and how much air sits between them.

Fine, powdery icing sugar traps a lot of air and weighs far less per cup than coarse granulated crystals. Brown sugar is damp and is normally pressed down into the cup, so a packed cup is heavier again. That is why a single rule such as 'one cup is 200 g' is right for white sugar and wrong for the other types.

If you only remember one thing, remember that you must know which sugar you are converting before you can divide.

Typical grams per US cup by sugar type

These figures are working averages, not exact standards. Published tables vary slightly (some give 198 g or 210 g for white sugar) because packing and humidity differ. For everyday cooking the 200 g figure is accurate enough, and for fine confectionery you should weigh the sugar and ignore cups altogether.

The conversion rule and the formula

Once you have the grams-per-cup figure for your sugar, the conversion is a single division. To go the other way, from cups into grams, you multiply.

A calculator takes the sugar type and the weight and handles the division and the fraction for you, which is useful for odd quantities like 135 g.

A worked example with three sugars

A cake recipe asks for 350 g of sugar, and you only own cup measures. How many cups is that? The answer depends on which sugar you actually have in the kitchen.

Now repeat for the other two with the same 350 g. Packed brown sugar at 213 g per cup gives 350 ÷ 213 = 1.64 cups, a little under 1 and 2/3 cups. Icing sugar at 120 g per cup gives 350 ÷ 120 = 2.92 cups, nearly 3 cups.

The same weight therefore needs 1.75, 1.64 or 2.92 cups depending on the sugar. If you had used the 200 g rule for the icing sugar you would have measured only 1.75 cups, which is about 210 g and 40 percent short of what the recipe wanted.

Which cup is your recipe talking about

The figures above use the US customary cup of about 236.6 ml. A metric cup used in Australia, New Zealand and many Indian recipes is 250 ml, which holds about 5.7 percent more. A 250 ml cup of white sugar weighs roughly 211 g rather than 200 g.

An old British cup, a glass tumbler or a coffee mug from the kitchen cupboard can be anywhere between 200 and 300 ml, so the only reliable approach is to match the cup that the recipe's author most likely used. When the source is an international food blog, assume the US cup. When it is a local cookbook that writes quantities in katori or glass, weigh what your own measure holds once and write the number on the container.

• Weigh one level cup of your own sugar a single time on a kitchen scale.
• Divide that weight into the grams in the recipe to get your own conversion.
• Note it on a sticky label so you never have to repeat the check.

Spoons and small amounts of sugar

For small quantities the same logic applies one level down. A US cup holds 16 tablespoons and 48 teaspoons, so granulated sugar at 200 g per cup works out to about 12.5 g per tablespoon and roughly 4.2 g per teaspoon. A recipe that asks for 25 g of sugar is therefore two level tablespoons.

• Level the spoon with a knife; a heaped teaspoon can hold double the amount.
• For brown sugar, press it into the spoon, which brings a tablespoon to about 13 g.
• For icing sugar a level tablespoon is only about 7.5 g, so 25 g takes more than three of them.

Teaspoon figures are good enough for tea and coffee, but baking is less forgiving. Sugar in a cake affects texture and browning as well as sweetness, so a 10 percent error in sugar is more noticeable in a sponge than in a cup of tea. When a result matters, borrow a kitchen scale; they are inexpensive, and weighing also cuts down the washing up because you can add ingredients straight into one bowl.

Measuring habits that change the answer

Even with the right density, the way sugar goes into the cup shifts the weight. Scooping directly from the bag compresses the crystals, while spooning and levelling gives a more repeatable result. For brown sugar, pack it firmly until the shape holds when you tip it out, because recipes that list brown sugar assume this.

Sifting icing sugar before measuring can drop a cup closer to 100 g, which matters if a frosting recipe lists cups of unsifted sugar. Check whether the recipe says 'sifted' or 'unsifted' before you sieve, and follow its wording.

Sugar also behaves differently from honey or syrup, which are liquids and are converted from grams using their own density of about 1.4 g per ml. Do not use the sugar table for them.