Cups to Grams Converter

Choose a direction, pick your ingredient, and type the amount. Cups to grams multiplies by that ingredient's weight per US cup; grams to cups divides by it. The reference line under the result shows the grams-per-cup figure being used, so you can see exactly where the number comes from. Everything runs in your browser and updates as you type.

Why cups and grams disagree

A cup measures volume, the space an ingredient fills, while a gram measures mass, the amount of matter present. A cup of feathers and a cup of lead take up the same room but weigh wildly different amounts, and the same holds in the kitchen: one US cup holds about 120 grams of all-purpose flour but 340 grams of honey. That is why no single number turns cups into grams. Each ingredient carries its own density, the mass packed into a given volume, and that density is what the selector switches between. Light, airy powders such as cocoa and rolled oats weigh little per cup, while packed sugars and thick syrups weigh a great deal.

From handfuls to level cups

For most of cooking's history there was no standard cup to convert from. Early recipes leaned on the cook's judgement and whatever crockery sat on the shelf. Amelia Simmons, whose American Cookery of 1796 was the first cookbook by an American author published in the United States, still called for a tea cup of coriander seed in one recipe and one glass of wine in another, for a piece of butter as big as a walnut, and for handfuls she never sized. Those vessels varied from house to house, so two cooks following the same page could end up with very different batters.

The turn toward precision is usually credited to Fannie Merritt Farmer, who led the Boston Cooking School and published The Boston Cooking-School Cook Book in 1896. Farmer is remembered as the mother of level measurements. She insisted that a cup or spoon be filled and then swept flat across the rim, so a cup meant one repeatable quantity rather than a rounded, generous scoop. Standardized cups and spoons followed, and American recipes have been written in level cups ever since.

The cup Farmer helped fix into place descends from the English wine gallon of 231 cubic inches, set in law by an act of Queen Anne passed in 1706 and in force from the following year. Britain dropped that gallon in 1826 when it went over to imperial measure, but the United States kept it. A US gallon holds sixteen cups, which makes one US cup eight fluid ounces. The exact metric value of 236.588 millilitres follows from the 1959 International Yard and Pound Agreement, which fixed the inch at exactly 2.54 centimetres: a cup is 14.4375 cubic inches, each cubic inch is 16.387064 millilitres, and the two multiply out to 236.5882365 ml.

Where the gram comes from

The gram on the other side of this converter grew from a very different tradition. In 1790, after Talleyrand put the question to the National Assembly, the French Academy of Sciences was asked to replace a tangle of regional weights with a single rational system. The law of 7 April 1795, the law of 18 Germinal Year III, named the gram and defined it as the absolute weight of a volume of pure water equal to a cube of one hundredth of a metre, at the temperature of melting ice. Mass was tied directly to length and to a substance every laboratory could obtain, which was the point: a gram would mean the same thing anywhere.

That definition still echoes in the kitchen. Because water has a density very close to one gram per millilitre, a US cup of 236.588 millilitres of water weighs almost exactly 236 grams, the figure in the table below. Denser or lighter ingredients simply move up or down from there.

The formula

grams = cups × density

Here density is the weight of one US cup of that ingredient. Going the other way, cups = grams ÷ density. With the defaults, 2 cups of all-purpose flour at 120 g per cup, the result is 2 × 120 = 240 grams. Two cups of flour weighing 240 grams is the most-checked figure in baking, and it anchors the rest: 1 cup is 120 g, 3 cups is 360 g. To reverse it, 240 grams divided by 120 grams per cup returns 2 cups.

Weights this converter uses

These follow standard US baking references. They are averages, not laws of physics, so a good scale still beats them for anything fussy.

Spoon and level, or you will be off

The largest source of error is not the ingredient, it is how you fill the cup. Dipping the cup into the bag and scooping compacts the flour and can pack in around 20 percent more than a gentle fill, turning a 120-gram cup into 145 grams, and King Arthur Baking reckons a thoroughly compacted cup can hold as much as 160 grams. The figures here assume the spoon-and-level method: spoon flour loosely into the cup, then sweep the top flat with the back of a knife. Flour also settles in the bag and takes on moisture in humid weather, so the same cup rarely weighs the same twice. That is the argument for a scale. A gram is a gram in a dry desert kitchen or a coastal one, which is why professional bakeries and most modern baking books lead with grams and treat cups as a convenience. Recipes that lean on exact ratios, such as bread, cakes, and laminated pastry, are the ones where the difference shows up most.

US cup versus metric cup

These weights are built on the US customary cup of 236.588 ml, the cup this tool assumes. A metric cup is 250 ml, roughly 6 percent larger, so a metric cup of flour comes out nearer 127 grams. Australia moved to the 250 ml cup during the metrication that followed its Metric Conversion Act of 1970, and four of those cups make exactly one litre. New Zealand uses the same cup. A third figure turns up on packaging: for nutrition labelling the US Food and Drug Administration treats a cup as 240 millilitres, so the serving sizes printed on a packet are not quite the cup a recipe means. The UK and much of Europe weigh dry ingredients in grams directly and rarely reach for cups at all, while Canadian recipes mix both, though the US cup is common. When a recipe already gives grams, use those grams. A chart is only a fallback for recipes written in cups, and it can never account for the flour brand, the humidity, or the hand doing the scooping.

Frequently asked questions

How many grams is 1 cup of flour?

One US cup of all-purpose flour weighs about 120 grams when you spoon it in and level the top. Scooping straight from the bag packs the flour and can push a single cup past 145 grams, which is why weighing beats measuring. So 2 cups is 240 g and 3 cups is 360 g.

Is a cup of sugar the same weight as a cup of flour?

No. Granulated sugar is denser, so one US cup weighs about 200 grams against 120 grams for all-purpose flour. Brown sugar packed into the cup is heavier still at roughly 220 grams. Swapping cup for cup without adjusting the weight is a common reason cakes turn out dense.

Why does my recipe give different gram amounts than this converter?

Ingredient weights vary between references because flour brands, humidity, and how firmly you fill the cup shift the number by 10 to 20 percent. This tool uses widely cited US baking figures such as 120 g per cup of flour and 200 g per cup of sugar. If your recipe lists its own gram weights, trust those over any general chart.

Does this work for a metric cup?

These figures assume the US customary cup of 236.588 ml, the standard in American recipes. A metric cup is 250 ml, about 6 percent larger, so a metric cup of flour lands nearer 127 grams than 120. Australian and some European recipes use the 250 ml cup, so check which one your recipe means.