About this tool
Scaling a recipe is straightforward arithmetic, but two practical issues come up: small ingredient amounts (like baking soda) sometimes don't scale linearly, and oven times don't change by the same factor as quantities. Use the calculator for scaling main ingredients; keep oven temp the same and watch carefully.
How it works
Enter the original recipe's servings and your desired servings. Enter up to 3 ingredient quantities and units. The calculator multiplies each by the scale factor.
The baker's percentage system
Professional kitchens use baker's math: every ingredient is expressed as a percentage of the flour weight. Flour is always 100%. This makes recipes scale linearly and lets you swap quantities without re-doing the math.
| Ingredient | Baker's % (lean bread) | Baker's % (enriched dough) |
|---|---|---|
| Flour | 100 | 100 |
| Water | 65-75 | 55-65 |
| Salt | 1.8-2.2 | 1.5-2.0 |
| Yeast (instant) | 0.5-1.0 | 1.0-2.0 |
| Sugar | 0 | 5-15 |
| Fat | 0-3 | 8-15 |
| Eggs | 0 | 10-25 |
Yeast conversions
| Type | vs instant yeast | Use when | Storage |
|---|---|---|---|
| Instant dry yeast | 1x | Default for breadmakers, mix directly into flour | 1-2 years freezer |
| Active dry yeast | 1.25x (use 25% more) | Older recipes, needs proofing in warm water first | 1-2 years freezer |
| Fresh / cake yeast | 3x (use 3x amount) | Professional bakers, very fresh result | 2 weeks fridge |
| Sourdough starter (100% hydration) | 20% of flour weight | Wild fermentation, longer bulk ferment | Weeks fridge, indefinite if fed |
Oven temperature conversions
| Description | °F | °C | Gas mark |
|---|---|---|---|
| Very cool | 275 | 135 | 1 |
| Cool | 300 | 150 | 2 |
| Warm | 325 | 165 | 3 |
| Moderate | 350 | 175 | 4 |
| Moderately hot | 375 | 190 | 5 |
| Hot | 400 | 200 | 6 |
| Very hot | 425 | 220 | 7 |
| Extremely hot | 450 | 230 | 8 |
| Maximum (pizza) | 475-500 | 245-260 | 9-10 |
Salt percentages for curing
Dry curing requires precise salt-by-weight calculations. Equilibrium curing uses 2.5-3.0% salt by total meat weight; nothing washes off. Pink curing salt (sodium nitrite) at 0.25% prevents botulism in long-cured products.
- Bacon: 2.5% salt, 0.25% pink curing salt #1, 1-2% sugar, cure 7 days per inch of thickness
- Pancetta: 2.5% salt, 0.25% pink curing salt #1, herbs and pepper, cure 14 days
- Coppa: 3.0% salt, 0.25% pink curing salt #2, cure 14-21 days then dry 60-90 days
Pink curing salt #1 (sodium nitrite only) is for cooked products (bacon, hot dogs). Pink curing salt #2 (nitrite + nitrate) is for long-dried products that don't cook (salami, prosciutto).
Hydration and dough strength
Hydration (water / flour by weight) controls the crumb structure:
- 50-55%: bagels, pretzels - dense, chewy
- 60-65%: standard sandwich bread - tight even crumb
- 65-70%: ciabatta, focaccia - irregular open crumb
- 70-80%: artisan sourdough - wild, lacy crumb
- 80%+: high-hydration sourdough (Tartine style) - requires high-protein bread flour and folds rather than kneading
The formula explained
This calculator uses the following formula:
scale = new_servings / original_servings; new_qty = old_qty × scale
The reason this formula works is rooted in the underlying physics, finance, or biology of the problem. Behind every calculator is a published, peer-reviewed equation or a widely accepted convention. We do not invent formulas; we apply standard ones from textbooks, government tables, professional bodies, and academic literature.
If you are curious about the math, the simplest way to verify is to plug in two known numbers and compare against a known result. The calculator should match published examples to within rounding precision.
Frequently asked questions
Do all ingredients scale linearly?
Most do, but baking soda, salt, and spices may not - start with 70-80% of the math result and adjust to taste.
How does cook time scale?
It doesn't - temperature stays the same, but volume changes can affect time. Larger pan = faster surface cook; deeper fill = longer center cook.
Halving an egg?
Beat the egg, measure half by volume (about 25g or 2 tbsp). Save the rest for pasta or scrambled eggs.
Doubling a cake?
Use two pans, not one bigger pan. The center of a deeper batch overcooks the edges before center sets.
How do I scale a recipe up or down?
Convert all ingredients to weight (grams), express as a percentage of flour (baker's math), then scale to your target flour weight. Eggs are tricky - one large egg is ~50g of liquid. Salt and yeast scale linearly. Fermentation time stays roughly constant; baking time scales with thickness.
Why does my bread come out dense?
Most common: under-fermentation. The dough should roughly double in bulk fermentation and pass the 'poke test' - poke a finger into the dough, the dent should slowly spring back about halfway. If it springs back fully, ferment longer; if it doesn't spring back at all, you're over-proofed.
Does altitude affect baking?
Yes. Above 3,000 ft (900m): reduce yeast 25%, reduce sugar slightly, increase liquid 1-2 tbsp per cup of flour, increase oven temp 15-25°F. Above 5,000 ft (1500m) standard recipes often need major rework.
How accurate are volume measurements?
Cups vary 10-20% by how packed the flour is. For baking, weight is 2-5x more reliable. A typical 'cup' of flour is 120-150g depending on aeration. Use a digital scale for any recipe where consistency matters.
Can I substitute instant for active dry yeast?
Yes. Use 75% as much instant for the same rise (instant is more potent and doesn't need proofing). Instant goes straight into the flour; active dry needs 5-10 minutes in warm water (110°F / 43°C) with a pinch of sugar to wake up.
How accurate is the Recipe Scaling Calculator?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Recipe Scaling Calculator free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Can I use the Recipe Scaling Calculator on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum.
Does the Recipe Scaling Calculator work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
How do I report a bug or suggest improvement to the Recipe Scaling Calculator?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours.
Can I share results from the Recipe Scaling Calculator?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another recipe scaling tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.