Cups to Grams Converter

How it works

Volume to weight conversion only works when you know the ingredient's density. The tool stores grams-per-cup for 30 common baking ingredients — flours, sugars, dairy, fats, sweeteners, and a few staples — and uses that table to translate. The default reference cup is the US customary 240 ml cup, which matches the cup printed on US measuring sets and the cup implied by most American recipe books.

For an unknown ingredient the converter returns a clear "no density on file" message rather than guessing, since a 50% error is the realistic range for an uninformed guess on something like chopped vegetables or shredded cheese.

Worked example

1 cup of all-purpose flour weighs about 125 g by this tool, 1 cup of granulated sugar is 200 g, and 1 cup of honey is 340 g. The same 1 cup shifts by nearly 3x depending on what's in it — which is why "1 cup of water = 240 g" is the easy case but the worst guide for baking. Convert ounces to grams by multiplying the ounce reading by 28.35 (or use the form for any of the six supported units).

Common mistakes

Don't scoop flour directly from the bag with the measuring cup — it compacts and you can end up 20% over. Fluff the flour, spoon it into the cup, and level with a straight edge; the converter assumes that lighter, properly-aerated weight. Brown sugar should be packed into the cup before leveling, which is why its gram-per-cup figure (220 g) sits above granulated sugar (200 g).

Don't trust volume conversions for ingredients not in the list. The form will say so explicitly; a wild guess there is worse than no answer.

FAQ

Why is a cup 240 ml and not 236.6 ml? US legal cups for nutrition labeling are 240 ml (8 fl oz × 29.5735 ml). US recipes in home cookbooks have historically used the 236.6 ml (8 fl oz × 29.5735 / 1.000) figure, but the difference is under 1.5% and most modern American sets mark the cup at 240 ml. Either way, the table values match what your measuring cup actually holds.

Does this handle metric volume (ml, l)? Yes — pick milliliters in the "from" dropdown and any weight unit in the "to" dropdown. The tool uses the density table the same way.

Can I add my own ingredient? Not from the page — the density table lives in `src/data/densities.json`. If you want a new ingredient added, open an issue and include a sourced grams-per-cup figure; unsourced additions get refused.