Asked.
Answered.

Linear quantities scale exactly — when the scaler doubles a recipe, every numeric quantity is multiplied by exactly two. Where rounding happens, it's by design: we round to the closest culinary fraction (denominators of 2, 3, 4, 5, 6, 8, 12, and 16) so the output stays measurable with the cups, spoons, and scales most kitchens own.

For weights, the displayed value is rounded to 1 g (or to 0.1 g for sub-gram quantities). For volumes, to within 1 ml. The internal computation is floating-point, so the rounding never compounds — a recipe scaled to 0.37× and back to 1× returns to the original ingredients exactly.

Because cooking time scales non-linearly with quantity, and the right rule depends on what you're cooking. A doubled pot of soup roughly doubles the time. A doubled cake takes longer, but not twice as long — the heat travels through the cube root of the volume change. A doubled tray of cookies barely changes at all. No single multiplier covers all three.

Our cooking-time guide gives sensible starting estimates for each geometry. We deliberately keep these out of the scaler itself, because over-confident time predictions cause more bad bakes than scaling ever does.

If a line doesn't start with a recognisable number — “a pinch of nutmeg”, “to taste”, “extra-virgin olive oil for finishing” — the scaler leaves it untouched. Those are judgement calls best left to a cook, not an algorithm. The same is true for instructions like “a generous splash” or “enough to coat the bottom of the pan”.

The scaler recognises:

• Whole numbers: 2, 15
• Decimals: 1.5, 0.75
• Fractions: 1/2, 3/4
• Mixed numbers: 1 1/2, 2 3/4
• Unicode glyphs: ½, ¾, 1½

Lines can be plain, bullet-prefixed, or dash-prefixed. Both US and metric units are recognised, and many synonyms (tsp, teaspoon, teaspoons; oz, ounce, ounces; etc.).

When the scaler produces a quantity in a small unit that's really a larger one in disguise, it promotes. Three teaspoons becomes one tablespoon. Sixteen tablespoons becomes one cup. Four cups becomes one quart. A thousand grams becomes one kilogram. Promotion only fires when the result is at least one unit of the larger size, so a recipe scaled by 1.25× still reads naturally.

A US cup is 236.588 ml. A metric cup is 250 ml — about 6% larger. Australian cups also use 250 ml, but Australian tablespoons are 20 ml (US and UK use 15 ml). All conversions on this site use US measurements unless explicitly noted. If you're cooking from an Australian or European cookbook with a US measuring cup, you can ignore the difference for everyday savoury cooking; for baking, switch to weight.

By weight, not volume. By volume, salts vary wildly because of crystal size: a cup of fine table salt weighs about 292 g, but the same volume of Diamond Crystal kosher salt is only about 142 g — less than half. Always convert salt by weight when swapping brands. The ingredient converter has separate entries for table salt, Diamond Crystal kosher, and Morton kosher.

Gas marks are a stepped scale used by British and Irish gas ovens. Each mark corresponds to a specific temperature, with rough increments of 25 °F (about 14 °C) per mark. The two most common settings are Gas 4 (the universal cookie/cake setting at 175 °C / 350 °F) and Gas 6 (moderately hot at 200 °C / 400 °F). Full table on the temperature converter.

Yes — usually. Most published recipes assume a conventional (non-fan) oven. If your oven has a fan (sometimes called convection or fan-assisted), reduce the recipe temperature by about 20 °C (or 25–30 °F), or shorten the cooking time by about 10–15%. Don't do both. Some modern ovens automatically apply this compensation; check your manual.

Often, but match by surface area rather than linear dimensions. A 9-inch round pan has roughly the same area as an 8-inch square (both about 64 in²), so the swap is clean. A 9-inch round vs. 9-inch square is a 25% difference — a noticeably different bake. Use the pan-size converter to check before you switch, and adjust temperature down 25 °F if the new pan is significantly larger.

Primarily from King Arthur Baking's ingredient weight chart — the most rigorously tested baking-ingredient density list publicly available — and the USDA FoodData Central database for non-baking pantry items. Where the two disagree, we use King Arthur for baking and USDA for everything else.

We pull recipes live from TheMealDB— an open, community-maintained database of cooked-and-tested recipes from around the world. ScaleRecipe is not affiliated with TheMealDB; we just love what they've built. Recipe data, photographs, and instructions are theirs.

Every recipe page has its own URL, so you can bookmark it directly in your browser — that's the simplest, most durable way to save a recipe. We don't currently offer accounts or saved-recipe lists, because we don't store user data of any kind.

TheMealDB's search is name-based — it matches against the dish name, not the ingredient list. Searching for “cumin” won't return Indian curries that use cumin, because cumin isn't in any dish's name. For ingredient-based discovery, use the category chips (chicken, beef, pasta, etc.) or search for cuisines (“Indian”, “Thai”).

No. The scaler runs entirely in your browser — recipe text never leaves your device. We don't run first-party analytics, don't fingerprint your browser, and don't require an account. The site does carry advertising via Google AdSense, which means Google may set cookies on your device for ad personalisation; see the Cookie Policy for the detail and opt-out links. Recipe search and translation make outbound network requests (TheMealDB and Google Translate respectively).

The scaler and all converters work without a network connection once the page is loaded — they're pure client-side code with no runtime dependencies. The recipe browser needs internet because it queries TheMealDB live; cached recipe pages will still display, but new searches will fail.

ScaleRecipe is a personal project. We're not currently distributing the source under an open-source licence. The interesting bits — the fraction-aware parser, the unit-promotion logic, the ingredient density table — are all documented on the relevant converter pages, so you can rebuild the techniques in your own kitchen tools.

Send us an email or open an issue on the project's feedback channel (link in the footer). Density submissions are particularly welcome if you have access to a calibrated kitchen scale and a reference standard — packing flour and weighing it is the lowest-tech, highest-impact data we collect.