Bread Calculator

A bakers' percentage calculator for yeasted bread doughs is the tool every serious home baker ends up needing. The whole idea behind bakers' percentages is straightforward once you have seen it once: instead of writing a recipe in cups or vague volumetric measures, every ingredient in the dough is expressed as a percentage of the total flour weight, which is normalised to 100%. So a 500 g flour dough with 325 g water, 10 g salt and 5 g yeast is reported as 100% flour, 65% hydration, 2% salt, and 1% yeast. Change the flour weight to 1,000 g and the same recipe gives 100% flour, 650 g water, 20 g salt and 10 g yeast, same percentages, double the dough. The system scales perfectly because every line is referenced to a single base value, and it is the universal language of modern bread baking.

This calculator does the bakers'-percentage arithmetic for you. Enter the total flour weight in grams, the hydration percentage, the salt percentage, the yeast percentage, and (if your recipe uses one) the preferment percentage. The calculator returns the mass of every ingredient in grams, the total dough weight, the breakdown of flour and water inside the preferment (so you know how much extra flour and water to add at mix time), and a per-loaf breakdown. Six presets cover the most common bread styles, lean white loaf, standard pan loaf, enriched dough (brioche or challah), poolish baguette, sourdough country loaf, and a two-loaf bake, so you can click and start scaling immediately. If you set a target finished loaf weight, the calculator also tells you how to adjust the flour to hit the target exactly.

How to Use the Bread Calculator

1. Click a preset (lean, standard, enriched, poolish, sourdough, two loaves) to load sensible starting percentages for that style of bread, or type your own values directly.
2. Enter the total flour weight in grams. This is your reference quantity, every other ingredient is expressed as a percentage of it.
3. Enter the hydration % (water ÷ flour × 100). Lean doughs run 60 to 75%, enriched doughs 55 to 65%, rye and whole-grain doughs can hit 80% or higher.
4. Enter the salt % (most breads sit between 1.8% and 2.2% by flour weight).
5. Enter the yeast % if you are using commercial yeast. Instant yeast at 1% is standard for a lean dough; enriched doughs use slightly more. Set to 0 if you are using a sourdough levain instead of commercial yeast.
6. Enter the preferment % if your recipe uses a poolish, biga, or sourdough levain. Typical values are 10 to 30% of total flour.
7. Click Calculate recipe. The result panel shows the masses of water, salt, yeast, and preferment, the total dough weight, the preferment breakdown (flour and water inside the preferment), and a per-loaf breakdown. If you set a target finished loaf weight, the calculator also suggests how to scale the flour to hit it exactly.
8. Use the live preview panel below the inputs to see the total dough weight update as you type, useful for fine-tuning hydration or salt on the fly.

The calculator accepts any positive flour weight and any percentage between 0 and 200 for hydration, 0 and 10 for salt and yeast, and 0 and 100 for the preferment. Values outside those ranges are rejected with a clear error message. Per-loaf calculations assume an average bake loss of about 12% of dough weight (mostly water lost as steam in the oven).

The Formula

Each ingredient mass is a simple multiplication of the total flour weight by the percentage and divided by 100:

Water = flour × hydration% ÷ 100

Salt = flour × salt% ÷ 100

Yeast = flour × yeast% ÷ 100

Preferment mass = flour × preferment% ÷ 100

Total dough = flour + water + salt + yeast

When the recipe includes a preferment (poolish, biga, or sourdough levain), the preferment itself already contains flour and water. The calculator assumes a 50/50 flour-to-water split inside the preferment, the standard assumption for a poolish and a 100%-hydration sourdough levain (see Beranbaum, The Bread Bible, 2003, and the King Arthur Baking Company guide). The preferment is therefore split as:

• Flour inside the preferment = preferment mass × 50%
• Water inside the preferment = preferment mass × 50%
• Final flour added at mix time = total flour − preferment flour
• Final water added at mix time = total water − preferment water

For a per-loaf breakdown, divide the total dough weight by the number of loaves:

Per loaf (raw) = total dough ÷ number of loaves

Per loaf (baked) ≈ raw per-loaf × 0.88 (about 12% average bake loss; ranges from 10% for a low-hydration enriched dough to 15%+ for a very high-hydration open-crumb sourdough).

If you set a target finished loaf weight, the calculator solves the same equation backwards: target total = target loaf weight × number of loaves, then the flour scale factor = target total ÷ current total, and the suggested flour weight = current flour × scale factor. The water, salt, and yeast lines scale by the same factor.

Worked Examples

Example 1, Lean white loaf. 500 g flour, 65% hydration, 2% salt, 1% instant yeast, no preferment. The result: 325 g water, 10 g salt, 5 g yeast, total dough 840 g. This is the baseline recipe for a baguette, ciabatta, or a free-form lean loaf. The dough comes together at about 65% hydration, easy to handle, holds its shape well in a banneton, and bakes into a tight-crumbed classic European-style loaf. Bake at 230 °C with steam for the first 12 minutes, then drop to 220 °C for the remaining 18 to 22 minutes.

Example 2, Brioche (enriched). 400 g flour, 55% hydration, 1.8% salt, 1.5% yeast, no preferment. The result: 220 g water, 7.2 g salt, 6 g yeast, total dough 633.2 g. Note the lower hydration, brioche looks like it should be wet because it is rich, but the eggs and butter add liquid. A typical brioche formula adds eggs at about 50% of flour weight (so 200 g of egg for this recipe) and softened butter at about 40 to 50% (160 to 200 g). Those additions are not part of the hydration line because hydration is water-to-flour only; they are folded in after the dough comes together.

Example 3, Poolish baguette. 500 g flour, 65% hydration, 2% salt, 0.4% yeast, 20% preferment. The poolish is 100 g, of which 50 g is flour and 50 g is water. So the final mix is 450 g flour + 275 g water + 10 g salt + 2 g yeast = 737 g of dough added at mix time. The total dough is 837 g (the poolish's 50 g flour and 50 g water are already in the totals). For two loaves, each raw portion is about 418.5 g, baking to roughly 370 g of finished baguette. The poolish is built the night before (12 to 16 hours at room temperature) and the final dough only needs 3 to 4 hours of bulk fermentation because most of the flavour development happened in the poolish.

Example 4, Sourdough country loaf. 800 g flour, 75% hydration, 2% salt, 0% commercial yeast, 20% levain. The levain is 160 g (80 g flour + 80 g water inside). The final mix is 720 g flour + 520 g water + 16 g salt = 1,256 g of final dough. Total dough 1,416 g (the levain's 80 g flour and 80 g water are already in the totals). One large boule, baked in a Dutch oven at 240 °C for 20 minutes covered and another 20 to 25 uncovered at 220 °C. The wild yeast in the levain handles all the leavening, so the commercial yeast line is zero. Long bulk fermentation (4 to 6 hours at room temperature plus overnight in the fridge) develops the open crumb and tangy flavour.

Example 5, Two loaves, target 900 g finished each. 1,200 g flour, 62% hydration, 2% salt, 1% yeast. The dough comes out to 1,980 g. Each loaf gets 990 g of raw dough, baking to roughly 870 g of finished loaf at 12% loss, close to the 900 g target. If you want exactly 900 g finished per loaf, set the target-loaf-weight field to 900 and the calculator will scale the flour up slightly. The water, salt, and yeast lines all scale together so the hydration, salt, and yeast percentages stay constant.

Where Bakers' Percentages Show Up

Bakers' percentages are the universal language of bread baking, and recognising them in the wild makes any bread recipe easier to scale, adapt, and troubleshoot.

• Home baking and recipe scaling. Every modern bread book uses bakers' percentages (Reinhart, Beranbaum, Hamelman, Suas, Forkish). Knowing how to read them lets you scale any recipe up or down without breaking the dough.
• Artisan bakeries. Commercial bakeries work in percentages so that a single recipe can produce 5 loaves or 500 from the same mixing bowl. The percentages never change; only the flour weight changes.
• Baking schools and competitions. Coupe du Monde de la Boulangerie and similar competitions require competitors to present formulas in bakers' percentages.
• Sourdough and wild-yeast baking. Levain hydration is always quoted as a percentage (a 100% hydration levain has equal weights of flour and water). Poolish, biga, and pâte fermentée each have characteristic hydration ranges.
• Food-science and product-development labs. Texture, crumb structure, and shelf life all correlate strongly with hydration, so QA teams report formulas in bakers' percentages for reproducibility.
• Gluten-free and alternative-flour baking. The percentages still work; the user just substitutes a non-wheat flour blend and adjusts hydration (most gluten-free doughs need more water than their wheat counterparts).

Common Mistakes

• Counting eggs and butter as hydration. Hydration is water-to-flour only. Eggs and butter contain water but are added separately and should not be folded into the hydration percentage.
• Forgetting that the preferment already holds flour and water. If you have a 20% poolish in a 500 g flour recipe, you only add 450 g of fresh flour at mix time, not 500. The poolish is 100 g of which 50 g is flour and 50 g is water.
• Referencing yeast to the preferment flour rather than total flour. A "0.4% yeast" line on a poolish baguette means 0.4% of the total flour weight, even though the yeast physically sits in the poolish. Bakers' percentages are always referenced to total flour, never to a sub-component.
• Treating hydration as a fixed target rather than a range. A recipe that calls for "65% hydration" usually means a range: 63 to 67% depending on flour brand, humidity, and how long the dough has rested. Flour absorbs water over time, so an autolyse or a longer bulk fermentation will tighten the dough even at the same hydration.
• Reporting salt as "to taste". Bakers' percentages are how salt is controlled precisely. Use 1.8 to 2.2% by flour weight; measuring by taste will under- or over-salt the dough by 30% or more.
• Confusing fresh yeast with dry yeast. A recipe that says "1% instant yeast" needs 3% fresh yeast (or cake yeast). The calculator handles dry yeast; multiply by 3 if you are using fresh.
• Weighing the finished loaf and assuming that is the dough weight. A 900 g finished loaf came from about 1,000 to 1,030 g of raw dough because bake loss is 10 to 15% (mostly water as steam). The calculator's "Per loaf (raw)" line is the dough weight you need to scale; the "Per loaf (baked)" line is just an estimate of the finished weight for reference.

Frequently Asked Questions

What is a bakers' percentage? A bakers' percentage (or baker's percentage) expresses every ingredient in a dough as a percentage of the total flour weight. Flour is normalised to 100%; everything else is reported relative to it. So a 65% hydration line means the water weight is 65% of the flour weight. The system is universal in bread baking because it scales cleanly: change the flour weight and every other ingredient scales by the same factor.

How do I scale a recipe from 500 g flour to 2,000 g flour? Multiply every ingredient weight by 4. The percentages stay the same; only the absolute masses change. A 500 g flour, 65% hydration recipe becomes 2,000 g flour, 1,300 g water, 40 g salt, 20 g yeast, same hydration, salt, and yeast percentages.

What hydration should I use for a beginner loaf? Start at 60 to 62% hydration for a standard pan loaf, or 65% for a lean free-form loaf. Lower hydration doughs are easier to handle (less sticky), higher hydration doughs are more open-crumbed but harder to shape. Baguettes and ciabatta sit around 65 to 75% hydration; brioche and enriched doughs sit lower (55 to 65%) because the eggs and butter add moisture.

How do I convert a volumetric recipe (cups) to bakers' percentages? Weigh every ingredient in grams on a kitchen scale, then divide each weight by the flour weight and multiply by 100. That gives you the percentage for each line. The result is reproducible across brands, humidity, and how tightly the original author packed the flour into the cup.

What is a preferment and when should I use one? A preferment is a portion of the dough's flour and water (and sometimes yeast) that is mixed ahead of time and fermented before being incorporated into the final dough. The three common styles are the poolish (equal weights of flour and water, a pinch of yeast), the biga (firmer, around 55% hydration), and the sourdough levain (flour and water fed with a wild-yeast culture). Preferments develop flavour, improve keeping quality, and reduce the final yeast dose.

What does "100% hydration levain" mean? A levain (or sourdough starter at feeding time) at 100% hydration has equal weights of flour and water. A 50% hydration levain is half water relative to flour. The hydration of the levain is independent of the hydration of the final dough: a 75% hydration final dough might be built with a 100% hydration levain.

How much yeast should I use? For instant yeast in a lean dough, 0.5 to 1% by flour weight is a typical range, 1% gives a 2 to 3 hour bulk fermentation at room temperature, 0.5% slows it down to overnight in the fridge. Enriched doughs use slightly more yeast (1 to 1.5%) because the sugar and fat slow the fermentation. Sourdough loaves use 0% commercial yeast, the wild yeast in the levain does all the work.

How much salt should I use? Standard bread sits at 1.8 to 2.2% salt by flour weight. Brioche and enriched doughs use slightly less (1.5 to 2.0%) because the fat masks the salt. Sourdough usually sits at 2%, the long fermentation softens the perceived saltiness. Salt controls fermentation rate (more salt = slower), tightens the crumb, and flavours the loaf. Going below 1.5% produces a flat, flavourless loaf; going above 2.5% noticeably inhibits the yeast.

How do I convert this for fresh yeast instead of instant? Multiply the instant-yeast weight by 3. So 5 g of instant yeast becomes 15 g of fresh (cake) yeast. The percentage stays the same in spirit but is usually reported as a different number because fresh yeast has roughly one-third the activity of instant.

Does bake loss change the percentages? No. Bakers' percentages describe the raw dough, not the finished loaf. A typical bake loss is 10 to 15% of dough weight (mostly water as steam), so a 1,000 g raw dough bakes to roughly 850 to 900 g finished loaf. The percentages are unaffected.

What is the difference between a poolish and a biga? A poolish is a liquid preferment at 100% hydration (equal weights of flour and water) with a small amount of commercial yeast. A biga is a stiffer preferment at about 55% hydration (less water relative to flour) with a similar small amount of yeast. Both are fermented for 12 to 16 hours before being incorporated into the final dough. The poolish contributes more open crumb and a milder flavour; the biga contributes more structure and a slightly more fermented flavour.

Can I use this for gluten-free bread? Yes, with two caveats. First, gluten-free doughs generally need more water than wheat doughs at the same hydration, a typical gluten-free loaf sits at 80 to 90% hydration because the alternative flours absorb less water than wheat gluten. Second, gluten-free doughs do not develop gluten structure, so they rely on binders (xanthan gum, psyllium husk) and longer fermentation for any crumb structure. Otherwise the calculator works exactly the same.

How accurate is the preferment breakdown? The calculator assumes a 50/50 flour/water split inside the preferment, which matches the standard poolish and a 100%-hydration sourdough levain. If your preferment is a stiffer biga (about 55% hydration, so slightly less water), the numbers will be off by a few grams, adjust the flour and water lines at mix time by hand. The total dough weight is unaffected by the split because the preferment mass is the same either way.

Sources and references:

• Beranbaum, R. L. (2003) The Bread Bible, W. W. Norton.
• Reinhart, P. (2001) The Bread Baker's Apprentice, Ten Speed Press.
• Hamelman, J. (2004) Bread: A Baker's Book of Techniques and Recipes (2nd ed.), Wiley.
• Suas, M. (2008) Advanced Bread and Pastry, Cengage.
• Forkish, K. (2012) Flour Water Salt Yeast, Ten Speed Press.
• King Arthur Baking Company, Bakers' Percentages guide (kingarthurbaking.com).
• Modernist Bread (2017), Nathan Myhrvold et al., The Cooking Lab.

References

• Baker percentage conventions, as used by King Arthur Baking and the Bread Bakers Guild of America. https://www.kingarthurbaking.com/blog/2024/01/17/bakers-percentage
• McGee, H. (2004), On Food and Cooking: The Science and Lore of the Kitchen, Scribner, for hydration ranges by dough type.