Cups to Grams for Liquids vs Dry Ingredients: Why Water Is Easy and Flour Isn’t
A cup of water weighs 236 grams. A cup of flour weighs 120. Same cup, same kitchen, half the weight. Converting cups to grams for liquids vs dry ingredients is really two different problems wearing one name, and most conversion charts pretend otherwise. Once you see why, you will stop trusting any chart that gives you a single number per cup without asking what is in it.
Start with the easy half. A US cup is 236.6 milliliters, a unit of volume. Grams are a unit of weight. The bridge between them is density, and for thin liquids the density sits very close to water's 1 gram per milliliter. So a cup of water weighs about 236 grams, a cup of milk about 240, and the conversion is barely a conversion at all: milliliters and grams are nearly the same number. If the liquid pours like water, 1 cup ≈ 236 grams is close enough for any recipe.
Cups to grams for liquids: the easy half, with one exception
The rule holds for water, milk, juice, broth, and wine. It breaks the moment the liquid gets thick or sugary, because density moves. A cup of vegetable oil weighs about 224 grams (oil is less dense than water, which is why it floats). A cup of honey weighs about 340 grams, nearly 50 percent more than water, because it is basically sugar with ambitions. Maple syrup lands around 315. So the real rule for liquids is: watery liquids, use 236 grams per cup and do not think twice. Anything viscous or syrupy, look it up.
Cups to grams for dry ingredients: the hard half
Dry ingredients are mostly air. A cup of flour is flour particles with air packed between them, and how much air depends on whether you spooned it in lightly or scooped it straight from the bag. Spooned and leveled, all-purpose flour runs about 120 grams per cup. Scooped, the same cup can hit 140 or more. That 20-gram swing is the difference between tender cookies and tough ones, and it happens inside a single "cup."
Sugar behaves better because the crystals pack consistently: about 200 grams per cup, granulated. Butter is the best-behaved of all at 227 grams per cup, because a stick is a manufactured object, not a pile of particles. Cocoa powder, sifted, sits around 100 grams per cup. Rolled oats land near 90. There is no formula here, only a lookup table. That is why our converter asks for the ingredient instead of pretending one multiplier fits all.
| 1 US cup of… | Grams | Why |
|---|---|---|
| Water | 236 | Density ≈ 1 g/ml; the baseline |
| Milk | 240 | Barely denser than water |
| Vegetable oil | 224 | Less dense than water |
| Honey | 340 | Dense sugar syrup |
| All-purpose flour (spooned) | 120 | Mostly air; method-dependent |
| Granulated sugar | 200 | Crystals pack consistently |
| Butter | 227 | Manufactured stick, no air |
Here is my practical take. Cups are a fine technology for water and everything that pours like it. They are a rumor for flour. If a recipe measures water in cups, convert at 236 and move on. If it measures flour in cups and the result matters, weigh it. A $15 kitchen scale eliminates the single biggest source of variance in home baking, which is not your oven. It is your cup.
One more trap: the cup itself changes by country. A US cup is 236.6 ml, but an Australian metric cup is 250 ml and a Japanese cup is 200 ml. If you are converting a recipe from abroad, check which cup the author meant before you convert anything. The grams do not care about borders, but the cups do.
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Run your own numbers with the free converterFrequently asked questions
How many grams are in a cup of water?
About 236 grams. A US cup is 236.6 milliliters and water's density is 1 gram per milliliter, so the numbers match almost exactly.
How many grams are in a cup of milk?
About 240 grams. Milk is barely denser than water, so 236 to 245 grams per cup all appear in published tables; 240 is the safe middle.
Why does a cup of oil weigh less than a cup of water?
Density. Oil is less dense than water (about 0.92 g/ml), which is also why it floats on water. A cup of vegetable oil weighs roughly 224 grams versus water's 236.
Can I use the same cups-to-grams conversion for all liquids?
Only for thin, water-like liquids: water, milk, juice, broth. Viscous or sugary liquids differ a lot: honey is about 340 grams per cup and maple syrup about 315. Look those up individually.
Is a metric cup the same as a US cup?
No. A US cup is 236.6 ml, an Australian metric cup is 250 ml, and a Japanese cup is 200 ml. When converting a foreign recipe, confirm which cup the author used first.
Related: Why Does My Cup of Flour Weigh Different Every Time? · Grams in a Cup of Flour, by Type · Cups to Grams Conversion Chart for Baking · How Many Grams in a Cup of Honey?
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