Methodology & data sources
Every result on CrumbCalc is computed from published, test-kitchen-grade reference data — not guessed and not generated by an AI model. Here's exactly what each tool uses and how it works, so you can trust the number.
Written and maintained by Maya Hartwell, recipe developer & home baker · Last reviewed: July 2026
Cups to grams — ingredient densities
A cup is a measure of volume, so converting it to grams needs a density for each ingredient. Our densities follow the King Arthur Baking ingredient weight chart — the reference most US test kitchens treat as standard — cross-checked against USDA FoodData Central. Flours assume the spoon-and-level method (all-purpose flour = 120 g per cup); brown sugar is measured packed, as recipes intend. Volume math uses the US legal cup of 236.588 ml. Volume↔volume and weight↔weight conversions are ingredient-independent; only volume↔weight uses the density.
Cake pan converter — capacities & batter depth
Pan capacities come from published manufacturer and test-kitchen measurements (King Arthur Baking and Wilton pan charts), with custom sizes falling back to geometric volume (1 US cup = 14.4375 cubic inches). The ingredient multiplier is the ratio of the two pans' capacities — a volume comparison, not a flat area one, which is why a deeper pan isn't treated the same as a wider one. Time and temperature guidance is driven by batter depth (volume ÷ area) assuming the standard two-thirds fill: deeper batter bakes longer at a lower temperature, shallower bakes faster. Always confirm with a toothpick.
Recipe scaler — fractions & safe limits
The scaler multiplies each ingredient by your factor and rewrites the result in fractions you can actually measure (it understands mixed numbers like "2 1/2", unicode fractions like "¾", and decimals). Lines with no quantity ("pinch of salt") pass through untouched, and fractional eggs are flagged with a practical fix. It warns beyond about 3× because leavening, salt, and strong spices don't scale linearly — professional bakers scale those to roughly three-quarters of the math and adjust to taste.
Oven temperature converter
Fahrenheit↔Celsius use the exact formulas (°C = (°F − 32) × 5/9). Gas marks follow the standard UK gas-mark table (gas mark 4 = 350 °F / 180 °C, "moderate"), and the fan/convection column applies the conventional −20 °C reduction (≈ 25–30 °F), since circulating air transfers heat faster than still air.
How we keep it accurate
The calculation engine is unit-tested, runs entirely in your browser, and is reviewed against its sources periodically (see the date above). CrumbCalc is built and maintained by Maya Hartwell, recipe developer & home baker — if you spot a number that looks off, please tell us and we'll check it against the references and correct it.