Why a cup of flour and a cup of sugar don't weigh the same
Here's the thing that trips up almost everyone: a cup is a measure of volume (how much space something takes up), while grams and ounces measure weight. To get from one to the other you need to know how heavy the ingredient is for a given amount of space — its density. Flour is light and fluffy, so a cup of all-purpose flour comes in around 120 grams. Granulated sugar is denser and packs in closer to 200 grams per cup. Honey is heavier still, roughly 340 grams a cup. That's why this tool asks you to pick an ingredient first — without it, "1 cup = X grams" is basically a guess.
If you're only going volume-to-volume (cups to tablespoons) or weight-to-weight (ounces to grams), density doesn't matter and you can skip the ingredient. It only comes into play when you cross between the two worlds.
Cups, tablespoons, teaspoons: the volume ladder
Volume units nest together in fixed ratios, no matter what's in the spoon. In the US system, 1 cup = 16 tablespoons, 1 tablespoon = 3 teaspoons, and 1 cup = 48 teaspoons. A US cup is 236.6 ml, a US tablespoon is about 14.8 ml, and a teaspoon is about 4.9 ml. These never change, so once you've memorized "3 teaspoons in a tablespoon, 16 tablespoons in a cup," you can do a lot of quick mental math at the counter.
One catch worth knowing: a US "stick" of butter equals 8 tablespoons, or half a cup, which is where the familiar "1 cup butter = 2 sticks" comes from.
US, metric, and imperial cups are not identical
The word "cup" hides a small regional trap. A US customary cup is 236.6 ml. The metric cup used in Australia, New Zealand, and much of Europe is rounded to 250 ml. The old imperial cup (still seen in some older UK recipes) is about 284 ml. That's roughly a 5–20% spread, which is usually fine for soups and stews but can matter in baking. If a recipe doesn't say, US recipes almost always mean the US cup, and modern British recipes increasingly give weights in grams precisely to sidestep the confusion.
Grams vs ounces and the weights worth memorizing
On the weight side, 1 ounce is 28.35 grams and 1 pound is 16 ounces (453.6 grams). These are exact, ingredient-independent conversions. A handful of weights cover a big chunk of everyday baking:
- 1 cup all-purpose flour ≈ 120 g
- 1 cup granulated sugar ≈ 200 g
- 1 cup packed brown sugar ≈ 220 g
- 1 cup butter ≈ 227 g (2 sticks)
- 1 cup water ≈ 237 g
- 1 cup milk ≈ 244 g
- 1 cup honey ≈ 340 g
Treat these as solid ballpark figures rather than laboratory constants — brand, humidity, and how you scoop all nudge them a little.
How to measure so your numbers actually hold up
The biggest source of error in dry ingredients is the scoop-and-pack habit. Dragging a measuring cup through the flour bag compresses it and can add 20% or more weight versus the "spoon and level" method, where you spoon flour loosely into the cup and sweep the top flat with a knife. For sticky liquids like honey or syrup, a quick coat of oil on the spoon helps everything slide off. And for liquids, read the line at eye level on a clear measuring jug rather than from above.
When to ditch cups and reach for a scale
For anything where structure matters — bread, pastry, macarons, layer cakes — weighing in grams is simply more reliable than volume. A digital kitchen scale removes the guesswork around packing and settling, lets you "tare" (zero out) the bowl between ingredients, and means fewer cups to wash. This converter is great for translating a recipe you already have, but if you bake often, weighing is the upgrade that quietly fixes a lot of inconsistent results.