Set original and new servings to compute the scale multiplier.
Pick the ingredient — densities differ a LOT (flour 120 g/cup; honey 340 g/cup).
Enter the amount in any common unit; the calculator shows it in cups, tbsp, ml, grams, and oz, then applies the multiplier.
For mass→volume conversions, set "from unit" to grams or ounces.

About this calculator

Two cooking conversions in one tool. Recipe scaling: multiply every ingredient by the ratio of new servings ÷ original servings — works linearly for most things, but reduce leavening (baking powder/soda/yeast) by 10-20% for 3×+ scale-ups. Cup → gram density conversion: 1 cup of flour ≠ 1 cup of sugar in weight because they have different densities. The ingredient picker uses King Arthur Baking's authoritative ingredient-weight chart, which is itself derived from USDA FoodData Central. For baking, weighing in grams is dramatically more accurate than measuring cups — cups vary by how packed the ingredient is. The volume↔mass conversion is the one cooking conversion that genuinely matters.

Frequently asked

Why are cup-to-gram conversions different for every ingredient?+

Density (mass per volume). A cup is a fixed volume (~237 mL); how many grams that volume weighs depends on the ingredient. Flour packs loose (120 g); honey is dense (340 g); brown sugar is packed (213 g). King Arthur Baking publishes the standard reference table.

Is the cup standard the same everywhere?+

No. The US legal cup is 240 mL; the US customary cup (used in recipes) is 236.588 mL; the metric cup (Australia, NZ) is 250 mL; the UK / Imperial cup is 284 mL. This calculator uses the US customary cup (236.588 mL) since most online recipes use it.

Does cooking time scale linearly?+

No — scale up by 2× and cooking time only goes up modestly (volume scales by 2× but surface area for heat transfer scales by 2^(2/3) ≈ 1.59). Add 5-15 minutes for a 2× scale-up; check earlier than the linear-scaled time.

What about salt and leavening?+

Salt: scales linearly up to 4× without issue. Leavening (baking soda/powder/yeast): reduce by 10-20% for 3×+ scale-ups to avoid metallic / fermented off-flavors.

Why do my baking results vary even when I weigh?+

Flour absorbs ambient humidity (1-3% mass swing); butter temperature affects creaming volume; oven thermostats can be ±25°F off. Weighing eliminates the BIGGEST variable but not all of them.

Source for densities?+

King Arthur Baking Co. ingredient-weight chart (US baker industry-standard) + USDA FoodData Central nutrient density per 100 g. Both are linked from the BLS data portals.