Recipe Scaler
Paste any recipe, change the serving count, and get scaled ingredient amounts with smart fraction display (1/2, 1/3, 3/4 instead of ugly decimals).
Recipe Scaler
How to use the Recipe Scaler
Paste the recipe ingredients
Copy ingredients from any cookbook, blog, or app and paste them into the left panel — one ingredient per line. The scaler parses the leading quantity from each line (supports integers, decimals, and fractions: "2", "2.5", "1/2", "2 1/2" all work). Anything without a leading number (like "salt to taste" or section headers) gets passed through unchanged.
Set original and new serving counts
"Original servings" is what the recipe was written for. "New servings" is how many you want to make. Cutting a 4-serving recipe to 2? Set 4 → 2. Scaling up a 6-serving recipe for a dinner party of 12? Set 6 → 12. The math handles any ratio — scaling a 1-serving recipe to 17 servings just works.
Read the scaled output in cooking-friendly fractions
Numbers get rounded to common kitchen fractions: 1/16, 1/8, 1/6, 1/5, 1/4, 1/3, 3/8, 1/2, 5/8, 2/3, 3/4, 5/6, 7/8. So a scaled "1.5" becomes "1 1/2", "0.33" becomes "1/3", "1.75" becomes "1 3/4". Decimals only appear when no clean fraction matches within 5% tolerance.
Mind the seasoning + spice scale break
Most recipes scale linearly for the bulk ingredients (flour, butter, sugar, liquids) but spices, salt, and aromatics scale sub-linearly. When doubling a recipe, use 1.5–1.75× the salt and 1.5× the spices, not 2×. When halving, use 0.6–0.7× the salt, not 0.5×. The scaler does linear math — adjust seasoning to taste after the first scaled batch. Yeast, baking powder, and baking soda also need adjustment — see the FAQ for baking-specific guidance.
Recipe scaling — why linear math fails for spices, yeast, and baking soda
Scaling a recipe is mostly arithmetic — multiply every ingredient by the scale factor (new servings / original servings) and you're done. For about 80% of ingredients, this works perfectly: flour, milk, butter, sugar, oil, water, eggs, meat, vegetables — all scale linearly. Where linear scaling breaks down is in three specific categories: seasonings (salt, herbs, spices), leavening agents (yeast, baking soda, baking powder), and surface-area-dependent items (oils used for greasing pans, eggwash quantities, breading depth). Knowing where to deviate from the math is the difference between a doubled recipe that tastes right and one that's painfully over-salted or won't rise.
The seasoning rule — 1.5× when doubling, 0.7× when halving
Salt, pepper, garlic, ginger, and dried herbs follow a perceptual scale, not a linear one. The Weber-Fechner law (which describes how human senses perceive stimuli logarithmically) means that doubling the salt in a doubled recipe makes it taste twice as salty, not equally salty. The empirical rule from cooking schools (Le Cordon Bleu, ICE, CIA all teach it): when scaling UP, use 1.5–1.75× the seasoning for a 2× recipe; when scaling DOWN, use 0.6–0.7× for a 0.5× recipe. This is why professional kitchens taste-and-adjust seasoning at the end rather than trusting the math, even when the underlying recipe is precise.
Linear math works for flour, butter, and sugar — but not for salt, spice, or yeast. Scale the bulk, then taste and adjust the seasoning by hand. The math gets you to the ballpark; your palate gets you home.
Baking has its own rules
Baking is chemistry, not just cooking — and scaling breaks down quickly. Yeast doesn't need to be doubled when you double the dough; the yeast colony grows exponentially, so 1.5× yeast for a 2× dough is plenty (and faster rises mean less flavor development — many bakers actually reduce yeast slightly when scaling up). Baking powder and baking soda scale closer to linear but should be adjusted by 0.85–0.9× when scaling above 1.5×, because larger batters trap more gas naturally. Pan sizes are critical: doubling a recipe in the same-sized pan changes baking time, temperature, and crumb structure completely. For baking, the safest scale-up is to make multiple batches in the same pan size rather than one giant batch.
The ASEAN home-cooking angle
Recipe scaling is universal but has some ASEAN-specific quirks. Rice quantities: 1 cup uncooked rice = ~3 cups cooked, serves 4-6 as a side dish; scaling for large family gatherings (Hari Raya / Chinese New Year / Diwali / Christmas / Lebaran) often involves 10×+ batch sizes where rice cooker capacity becomes the constraint, not the math. Curry pastes + sambals: scale sub-linearly because aromatic intensity is perceptual; 2× rendang base doesn't need 2× chillies. Soy sauce, fish sauce, kecap manis: all umami-heavy seasonings that follow the salt rule (1.5× when doubling). Pandan leaves, lemongrass, galangal, kaffir lime leaves: scale even more sub-linearly because the volatile oils don't accumulate in the dish proportionally — use 1.3-1.5× for a 2× batch. The good news: this calculator does the bulk math; your tongue and traditional family recipes do the seasoning calibration.
10 Things to Know About Recipe Scaling
Recipe scaling is mostly linear arithmetic — multiply every ingredient by the scale factor. Works for ~80% of ingredients (flour, butter, sugar, liquids, meat).
Salt and spices follow the Weber-Fechner law — perceived intensity is logarithmic, not linear. When doubling a recipe, use 1.5× the salt, not 2×.
Yeast is a living organism that grows exponentially. Doubling a dough only needs ~1.5× yeast; the colony multiplies itself to fill demand.
Baking is the hardest thing to scale because pan size matters as much as ingredient ratios. Doubling in the same pan changes baking time, temp, and texture.
The kitchen fractions humans use intuitively — 1/2, 1/3, 1/4, 3/4, 1/8 — match the markings on standard US measuring cups and spoons.
Professional chefs measure by weight (grams) not volume (cups) — flour cup-measure varies by ±20% depending on packing density, weight is exact.
1 US cup = 237 mL, but 1 UK / Commonwealth cup = 250 mL. UK / AU / NZ recipes overshoot if you use a US cup; US recipes undershoot if you use a UK cup.
1 tbsp = 3 tsp in every measurement system globally — the one universal kitchen conversion that doesn't vary by country.
Halving a recipe with "1 egg" is a classic scaling problem. Solutions: beat the egg first, weigh out half; or use 1 yolk for half; or scale to 0.5× of all eggs and accept "almost half" precision.
Cooking time doesn't scale linearly with quantity. A 4-pound roast doesn't take 2× the time of a 2-pound roast — heat transfer scales by surface area, not mass. Increase 30-50% for doubled portions.
Frequently Asked Questions
-
Salt and spices follow the Weber-Fechner perceptual law — your tongue perceives concentration logarithmically, not linearly. Doubling salt in a doubled recipe makes it taste twice as salty, not the same. The cooking-school rule: when doubling, use ~1.5× the salt; when halving, use ~0.7× the salt. The bulk ingredients (flour, butter, etc.) scale linearly through the calculator; you should adjust seasoning by taste after the first batch.
-
Yeast is a living organism that multiplies during fermentation, so it doesn't need to scale linearly. For doubled dough, use ~1.5× the yeast. For tripled dough, ~2× yeast. Some bakers actually reduce yeast slightly when scaling up to encourage longer, more flavorful fermentation. For halving, use 0.6× yeast — too little yeast is recoverable (longer rise) but excess yeast over-proofs the dough fast.
-
Up to ~1.5× usually works in the same pan size — baking time may need 10-15% more. Above 1.5×, you need a larger pan AND adjusted baking time (lower temp + longer time for thicker batters), or you should make multiple batches at the same pan size. Doubling a cake in the same pan typically produces a denser, undercooked center because heat transfer doesn't keep up. For cookies and individual pastries, scaling is safer because each piece is independent.
-
Three options: (1) Beat the egg in a small bowl, then use a scale or measuring spoon to take half (~25g of beaten whole egg). (2) Use just the yolk for half scaling (~17g) — works for binding, doesn't give the leavening of whites. (3) Round up to 1 whole egg and accept the recipe is slightly egg-heavy — usually fine for cookies, frittatas, and casseroles. For recipes where egg ratio is critical (souffles, mayonnaise), use option 1 with a scale.
-
No — cooking time scales with surface area, not mass. A 4-pound roast doesn't take 2× the time of a 2-pound roast; it takes maybe 1.4-1.5×. For most dishes, plan on 25-50% more time when scaling up 2×, 60-90% more when scaling up 3×. Use a thermometer for internal doneness rather than trusting time. For boiling / simmering on the stovetop, recovery time after adding cold ingredients matters more than scale — preheat the larger pot longer.
-
Yes — any recipe with one ingredient per line works. The parser handles integers (2), decimals (2.5), fractions (1/2), and mixed numbers (2 1/2). Lines without a leading number (like "Salt to taste" or section headers like "FOR THE SAUCE:") pass through unchanged. If your source uses unusual notation (e.g. "Two and a half cups"), edit it to numeric form first. The tool doesn't understand spelled-out numbers or units in non-Latin scripts.
-
Because cooking happens in cups and spoons, not decimals. The output uses common kitchen fractions (1/8, 1/4, 1/3, 1/2, 2/3, 3/4 etc.) that match the markings on standard US measuring cups and spoons. If the scaled value doesn't fall within 5% of a common fraction, the output falls back to a decimal. This makes it easy to read while measuring — "1 1/2 cups" is what you'll actually measure, not "1.5 cups".
-
Because volume measurements (cups) have ±20% variance depending on how the ingredient is packed. Sifted flour vs scooped flour vs spooned flour all give different gram weights for the same "1 cup" measurement. Weight is exact: 120g of flour is 120g of flour regardless of how it was packed. Professional bakeries weigh everything; serious home bakers do too. For consistent results when scaling, convert volume recipes to weight first (King Arthur Baking and Joy of Cooking both publish ingredient density tables).
-
No. All scaling runs entirely in your browser via JavaScript. There's no server roundtrip — open DevTools → Network and confirm zero outbound requests as you change inputs. Your recipes stay on your device. Safe for proprietary family recipes, restaurant test menus, or any culinary IP that shouldn't leave your machine. Close the tab and nothing remains.
-
Yes — the scaler is unit-agnostic and only reads the leading numeric quantity. It works for cups, tablespoons, grams, milliliters, ounces, ladles, "to taste" annotations, or any other unit-of-measure. The aromatic-scaling rule (1.5× when doubling) applies more strongly to ASEAN / South Asian / Middle Eastern cuisines because aromatic intensity dominates — scale chilies, lemongrass, ginger, garlic, cumin, cardamom sub-linearly. For rice dishes specifically: rice scales linearly, but cooking water adjusts because rice cooker capacity has fixed thermal mass; expect 10-15% less water per cup when batching large quantities.
Related News
You may be interested in these recent stories from our newsroom.
No related news yet for this tool. Our editorial team publishes new pieces every week.
Browse all news →75 more free tools
Calculators, converters, security tools — no signup.