Every gram-per-cup figure traces to King Arthur's chart. Where the chart lists a smaller measure, it has been scaled up to a full cup — the chart gives butter as 113 g per half cup, so this page uses 227 g per cup; honey as 21 g per tablespoon, so 336 g per cup. Seasonings are listed per teaspoon or tablespoon and multiplied accordingly. The tests verify each of those conversions against the original chart row, so a typo cannot ship.
King Arthur was chosen because it is the most widely used weight chart in American home baking, it is published openly, and it is internally consistent. Consistency matters more than which chart you pick. Other reputable sources differ by a few grams per cup; mixing two charts in one recipe causes more trouble than following either one.
King Arthur treats a cup of liquid as 8 ounces, which is 227 g. A US cup of water actually weighs about 236 g — the "8 fluid ounces equals 8 ounces" equivalence is a convention, not physics, and it is only even close for water. The 4% gap is irrelevant for liquid in a batter, and following one chart consistently beats chasing the difference, so this page uses 227 g. If you are doing something where 4% on a liquid matters, weigh from the physics.
Beyond technique, real ingredients vary: humidity changes flour weight by a few percent, brown sugar depends entirely on how hard you pack it, and "chopped" nuts depend on how finely you chopped them. Grated cheese and breadcrumbs are the worst offenders, since the particle size sets the density.
| It does | It does not |
|---|---|
| Multiply every ingredient it can read, convert to a friendlier unit when the number gets awkward, and round to fractions a measuring spoon can actually hit. | Adjust pan size, bake time, or oven temperature. Those do not scale linearly and it would be guessing. |
| Pass through anything it cannot confidently read — headings, "salt to taste", notes — exactly as you typed it. | Understand the recipe. It is parsing text, not cooking. Always read the scaled list before you use it. |
Scaling is arithmetic; baking is chemistry. Ingredient ratios generally hold up to about double or half. Beyond that, leaveners (baking soda and powder) and salt often want a slightly smaller multiple than everything else, and very large batches behave differently in mixing and baking. Yeast doughs and custards are particularly unforgiving. When in doubt, make the recipe twice rather than doubling it once.
Pan comparisons use surface area, assuming the same batter depth — that is what determines how fast something bakes. Real pans vary: measure across the top, inside the rim. Bundt and tube pans are approximated, since their shapes differ by manufacturer, and any pan should be filled no more than about two-thirds.
Gas marks follow the standard UK scale, where mark 1 is 275 °F and each mark is 25 °F. The convection adjustment is the conventional −25 °F (about −15 °C); individual ovens vary, and a recipe that already says "fan" has the adjustment built in. Home ovens are also frequently 25–50 °F off at the dial, which no converter can fix — an oven thermometer can.
This tool converts numbers. It knows nothing about allergens, substitutions, food safety, internal cooking temperatures, or storage. Do not rely on it for anything where getting it wrong would make someone ill.
Provided free, as-is, without warranty of any kind. The author is not liable for any loss, damage, or ruined dinner arising from its use. King Arthur Baking is not affiliated with this tool and has not endorsed it; their chart is cited as a published source.