Cups to Grams Converter

The Cups to Grams Converter translates any volume between US cups and grams for eight common baking and cooking ingredients. Enter a value in either field and the other updates instantly, while the ingredient dropdown chooses the density that drives the conversion. The converter is useful for home bakers following European recipes that quote ingredient quantities in grams, cooks adapting American recipes to use a kitchen scale, food bloggers cross-publishing recipes between metric and imperial audiences, parents preparing infant formula or baby food where gram accuracy matters, students doing density or unit-conversion problems, and anyone who has ever wondered whether a "cup of flour" actually weighs 120 g or 150 g. The conversion is exact, the cup-to-millilitre step is defined by NIST SP 811, and the ingredient-density values are published by USDA FoodData Central and the King Arthur Baking Company ingredient-density reference table.

How to Use the Cups to Grams Converter

1. Pick an ingredient from the dropdown, the density value (in g/mL) that drives the conversion is shown next to each label.
2. Type a number into the Cups (US) field to see the equivalent in grams on the right.
3. Type a number into the Grams field to see the equivalent in cups on the left.
4. For the Cups to Grams Converter, The two fields stay in sync as you type, editing one updates the other automatically.
5. Use the quick presets for common baking quantities (1/4 cup flour, 1/2 cup sugar, 1 cup butter, 1 cup water, 1/3 cup honey) to load an exact pair of values instantly.
6. Read the result box to see the active formula, the chosen ingredient, the density in g/mL, and the current value side by side.

The Conversion Formula

The conversion between cups and grams sits on top of two physical facts: the volume of a US legal cup and the density of the ingredient being measured. Formally:

Cups to grams: grams = cups × 236.588 × density

Grams to cups: cups = grams ÷ (236.588 × density)

The constant 236.588 mL is the volume of a US legal cup (sometimes called the US customary cup) as defined by NIST SP 811 and the FDA labelling regulations. The density ρ is measured in grams per millilitre (g/mL), and for an ingredient like water it is essentially 1.00 g/mL, for which the formula collapses to the familiar "1 cup of water = 236.588 g" shortcut.

Because the cup-to-millilitre step is exact and the density is a published measured value, the conversion carries no rounding beyond the four-decimal display. If you switch ingredients, the formula re-uses the same cup value but multiplies by the new density.

Ingredient Density Table

The converter uses the following published densities (g/mL) for the eight built-in ingredients. Values are typical bulk densities for the ingredient as measured in a US measuring cup, not the pure-substance density.

Why the densities differ. Water defines the gram-to-millilitre relationship at 1.00 g/mL because the gram was originally defined as the mass of one cubic centimetre of water. Other ingredients are denser (honey, milk) or much less dense (flour, rice) because their molecules pack more or less tightly per unit volume. Butter is very close to water because it is mostly water by mass, about 80 % fat, 16 % water, 2 % milk solids, and the small difference comes from the fat and air content.

How the densities are measured. Flour density is measured by sifting the flour into a measuring cup and levelling the top with a straight edge, then weighing the contents. Sugar is measured the same way. Liquids are measured by pouring into a liquid measuring cup and reading the meniscus at eye level. Packed brown sugar, scooped flour, and oils poured thick can all produce higher apparent densities than the table values, see the Common Mistakes section below.

Worked Examples

Example 1, One cup of water. A recipe asks for 1 cup of water. How many grams is that? grams = 1 × 236.588 × 1.00 = 236.588 g. So 1 cup of water weighs 236.6 g, matching the well-known conversion and useful as a sanity check.

Example 2, A half cup of flour. A recipe calls for 1/2 cup of all-purpose flour. How many grams is that? grams = 0.5 × 236.588 × 0.53 = 0.5 × 125.39 = 62.70 g. So 1/2 cup of sifted flour weighs about 62.7 g. A full cup is 125.4 g, which is roughly half of what most people intuitively guess; the discrepancy is because flour is mostly air.

Example 3, One cup of honey. A recipe calls for 1 cup of honey. How many grams is that? grams = 1 × 236.588 × 1.42 = 335.95 g. So 1 cup of honey weighs about 336 g, note that honey is denser than water, so it weighs more per cup than the same volume of water.

Example 4, Two cups of butter. A recipe calls for 2 cups of butter. How many grams is that? grams = 2 × 236.588 × 0.96 = 454.25 g. So 2 cups of butter weighs about 454 g, which matches the kitchen convention that "1 lb of butter = 2 cups" (1 lb = 453.6 g, close to within 0.2 %).

Example 5, One cup of milk. A recipe calls for 1 cup of whole milk. How many grams is that? grams = 1 × 236.588 × 1.03 = 243.69 g. So 1 cup of milk weighs about 243.7 g, slightly more than water because milk is about 12 % solids by mass (lactose, protein, fat) that add density.

Example 6, Working backwards from grams. A European recipe gives 300 g of flour. How many cups is that? cups = 300 ÷ (236.588 × 0.53) = 300 ÷ 125.39 = 2.39 cups. So 300 g of flour is about 2.4 cups. The cups field shows the rounded value; the grams field stays as the canonical input.

Example 7, Switching ingredients mid-recipe. You start with 1 cup of water (236.6 g) and now need the same volume of olive oil. Select olive oil from the dropdown with the cups value still at 1. The grams field updates to 217.7 g. The mass has dropped because olive oil is less dense than water by about 8 %.

Where the Conversion Shows Up

• Home baking: Adapting European metric recipes (which quote grams) to American cup-based recipes, and vice versa. A kitchen scale combined with this converter is the most reliable way to convert.
• Recipe scaling: Rescaling a recipe by a factor (halving, doubling, tripling) preserves the grams-per-cup ratio, so the converter gives the same answer per cup regardless of batch size.
• Food labelling and nutrition: FDA nutrition labels in the US list serving sizes in grams, but home recipes are written in cups. The converter bridges the two.
• Cookbook publishing: Editors checking that printed cup measurements reproduce the intended gram weight when the recipe is followed by a kitchen scale.
• Food science and product development: Process engineers and food chemists switching between volume and mass for batch sheets, where the cup is a kitchen unit and the gram is a laboratory unit.
• Education: Teaching the relationship between volume and mass, the meaning of density, and the conversion chain cups → millilitres → grams.
• Infant feeding and clinical nutrition: Convert gram measurements on infant formula or medical-food packaging into cup measurements for practical use, while keeping the gram value as the precise intake target.

Common Mistakes

• Using the wrong cup size. A US legal cup is 236.588 mL. A US customary cup used in older recipes is the same volume. A US fluid cup (used in some Australian recipes) is 240 mL. A UK imperial cup is 284.131 mL. A metric cup (used in Australia and New Zealand) is 250 mL. If the recipe or scoop comes from a source that uses a non-US cup, the answer will be off by 1 % to 20 %.
• Scooping flour instead of spooning it. Scooping flour straight from the bag with the measuring cup compacts the flour and produces a much higher density (often 0.65 to 0.75 g/mL). The right technique is to spoon the flour into the cup and level it with a straight edge. The 0.53 g/mL value in this converter assumes the proper spoon-and-level technique.
• Treating sifted and spooned flour as the same. Sifted flour is less dense than spooned flour by about 10 %. Most modern recipes assume spooned-and-levelled flour; sifted flour is now uncommon in published recipes.
• Assuming packed brown sugar has the same density as granulated sugar. Packed brown sugar has a density closer to 0.93 g/mL (about 220 g per cup). The table value of 0.85 g/mL is for granulated sugar only.
• Converting by weight but reporting by volume. If a recipe specifies 200 g of flour, the equivalent is 1.6 cups by volume, but the same recipe re-printed in cups will say "1 3/4 cups" because home cooks round to the nearest practical fraction. The converter gives the precise value; the recipe author rounds.
• Mixing mass and volume for liquids. One cup of water is 236.6 g and 236.6 mL. One cup of milk is 243.7 g and 236.6 mL. The volume is the same; the mass differs by density. Always check whether the recipe intends mass or volume before using the converter.
• Forgetting that 1 cup of butter ≈ 2 sticks. US butter is sold in 1-stick (113 g) and 4-stick (454 g) packages. "1 cup butter" equals 2 sticks or 227 g. If a recipe says "1 stick of butter," that's 1/2 cup or 113.5 g.

Quick Mental Conversion Trick

For water, milk, and other liquids close to 1 g/mL, one cup ≈ 240 g. That's the rough mass equivalent, accurate to within about 1.5 %.

For flour, sugar, and other baking ingredients, the rule of thumb is 1 cup of flour ≈ 125 g and 1 cup of sugar ≈ 200 g. Both are within 2 % of the table value.

For honey, syrup, and other dense liquids, 1 cup ≈ 340 g, which is about 40 % more than water.

For fats (butter, oil), 1 cup ≈ 225 g, close to 1 cup of butter (227 g) and 1 cup of olive oil (218 g).

These tricks are most accurate when the ingredient is measured the standard way (spooned and levelled for dry ingredients, meniscus reading for liquids). For laboratory, commercial baking, or scaled-up production work, use the exact table value.

When to Use a Different Tool

This converter is precise enough for home baking and most recipe work. For commercial or industrial baking where ingredient weights must be batch-traceable, use a calibrated kitchen scale reading directly in grams rather than converting from cups, the scoop-to-scoop variation in cup measurement is the largest source of batch-to-batch inconsistency in bakery production. For nutritional analysis of a finished dish, use the ingredient's mass as recorded by the scale, not the cup equivalent. For laboratory work, the gram is the only mass unit that matters; the cup is a kitchen convention and disappears entirely in lab settings.

Frequently Asked Questions

How many grams are in one cup of flour? One cup of sifted, spooned-and-levelled all-purpose flour weighs about 125 g (specifically 125.4 g using the 0.53 g/mL density). If you scoop the flour directly from the bag with the measuring cup, the weight will be higher, often 140 to 150 g, because scooping compacts the flour. Use the spoon-and-level technique for accuracy.

How many grams are in one cup of sugar? One cup of granulated sugar weighs about 201 g (201.1 g using the 0.85 g/mL density). Packed brown sugar is denser at about 220 g per cup. Powdered (confectioners') sugar is slightly less dense than granulated sugar at about 120 g per cup.

How many grams are in one cup of butter? One cup of butter weighs about 227 g (227.1 g using the 0.96 g/mL density). That equals 2 US sticks of butter or 1/2 pound. The kitchen convention that "1 lb of butter = 2 cups" gives 453.6 g for 2 cups, which matches the formula to within 0.2 %.

How many grams are in one cup of water? One cup of water weighs exactly 236.588 g (1 cup = 236.588 mL, and water has a density of 1.00 g/mL). This is the most accurate conversion in the table and a useful sanity check for the calculator.

How many grams are in one cup of honey? One cup of honey weighs about 336 g (335.95 g using the 1.42 g/mL density). Honey is denser than water because of its high sugar content, sucrose, fructose, and glucose all pack more mass per millilitre than water.

How many cups are in 100 grams of flour? 100 grams of all-purpose flour is 100 ÷ 125.4 = 0.80 cups, or about 3/4 cup plus 2 teaspoons. The cups field on the converter shows 0.7974 with the flour ingredient selected.

can the Cups to Grams Converter be used for professional or commercial purposes? Yes, the calculator provides results that are mathematically correct to the precision shown and are suitable for recipe development, food blogging, and home cooking. For commercial baking, pharmaceutical compounding, or any legally regulated application, verify results with a domain expert and use a calibrated instrument traceable to national standards. The cup-to-millilitre conversion is exact by NIST definition; the ingredient densities are published reference values that may vary by brand, growing region, or measurement technique.

How often are the underlying ingredient densities updated? The cup-to-millilitre constant (236.588 mL) is fixed by NIST SP 811 and the FDA labelling regulations and rarely changes. The ingredient densities are published reference values from USDA FoodData Central and the King Arthur Baking Company ingredient-density table. When these sources revise a value (for example, a new measurement of sifted flour density), this calculator is updated to reflect the current authoritative source. The density table on this page lists the specific values used.

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References

• USDA FoodData Central, the authoritative database of nutrient and density data for foods sold in the United States. The ingredient densities used here match the bulk-density values published in the FDC measurement files.
• NIST Special Publication 811, Guide for the Use of the SI Units, defines the US legal cup as exactly 236.588 mL and the relationship between volume and mass units.
• King Arthur Baking Company, Ingredient Weight Chart, the most widely cited baking reference for cup-to-gram conversions of flour, sugar, butter, and other baking ingredients. The densities for butter, flour, and sugar in this calculator match King Arthur's published values to within 1 %.
• FDA 21 CFR 101.9, Nutrition Labelling of Food, defines the US legal cup for serving-size declarations on packaged food labels.
• The Century Dictionary and Cyclopedia (1911), historical source for the definition of the US customary cup and its relationship to other volume units.
• USDA FoodData Central entries for Wheat flour, white, all-purpose, enriched, bleached (FDC ID 169736) and Honey (FDC ID 169640), primary density and water-content values that anchor the table above.