Why use this calculator
Baker's percentage is the only recipe language that scales cleanly, because every ingredient is quoted against total flour at 100%. That works beautifully until a preferment enters the picture, which is where most home bakers go wrong: they build a 200 g levain from 100 g of flour and 100 g of water, then add the full recipe flour and water on top.
The loaf ends up with 20% more flour than the formula intended and a hydration nowhere near the number on the page, so the crumb is tight and the dough feels stiff for reasons that never get diagnosed. This calculator keeps the preferment inside the denominator and tells you what is left to add at the final mix, which is the only pair of numbers you actually weigh out.
How to use it
- Enter the total flour weight, counting every gram of flour in the finished loaf including whatever you already fed to the levain last night.
- Set the hydration you are aiming for, using the band guide beside the result if you are not sure.
- Salt sits between 1.8 and 2.2 per cent for nearly every bread, so leave it near two unless the formula says otherwise.
- Set yeast to zero if a levain is doing all the leavening, or around one per cent for a same-day loaf.
- Enter the flour that went into your preferment and the hydration of that preferment, which is 100 per cent for a liquid levain or poolish and about 50 per cent for a stiff biga.
- Finally, say how many loaves you will divide the dough into so you get a scaling weight per piece.
What each result means
- Total flour
- The 100% figure that every other percentage is measured against, including flour already fed to the preferment.
- Total water
- All the water in the finished dough, including whatever is already carried in the levain or biga.
- Salt
- Weight of salt for the batch. Below 1.5 per cent the loaf tastes flat and the gluten stays slack.
- Yeast
- Instant dry yeast for the batch. Halve it for a slow overnight rise, or set it to zero for a pure levain build.
- Preferment weight
- What your levain, biga or poolish weighs on the scale once its flour and water are added together.
- Flour to add at final mix
- The flour you actually weigh into the bowl, after subtracting what is already in the preferment.
- Water to add at final mix
- The water you actually weigh into the bowl. Hold back fifty grams if the flour is new to you.
- Total dough weight
- Everything in the bowl before baking. Expect the baked loaf to weigh roughly ten to fifteen per cent less.
- Dough weight per loaf
- Scaling weight for each piece after dividing, which is how bakeries get loaves of a consistent size.
- Dough hydration
- Total water divided by total flour, the single number that predicts how the dough will handle.
- Preferment as a share of the flour
- How much of the total flour was pre-fermented. Higher shares mean faster fermentation and more sour flavour.
The formula
Every weight is a percentage of total flour:
- Water = total flour x hydration / 100
- Salt = total flour x salt percentage / 100
- Yeast = total flour x yeast percentage / 100
Total flour means the flour in the final mix plus the flour already in the preferment, and total water likewise.
Preferment water = preferment flour x preferment hydration / 100
What you weigh at the final mix is flour at mix = total flour minus preferment flour
Water at mix = total water minus preferment water
Total dough weight = flour + water + salt + yeast, and dough per loaf is that total divided by the number of pieces
How this number is used in practice
Hydration is really a description of how the dough will feel in your hands rather than a quality target. A sandwich loaf at 55 to 65 per cent holds its shape on the bench, takes a tight shaping and slices cleanly for toast. A country sourdough at 70 to 80 per cent needs coil folds instead of kneading and rewards you with a glossy, open crumb.
Above 80 per cent, as in ciabatta and focaccia, the dough is closer to a thick batter: you handle it with wet hands in a tub, and it wants a tin or a couche rather than a free-standing shape. None of these is more advanced than the others, they simply need different handling.
Flour choice moves the goalposts more than most bakers expect. Wholemeal and rye carry bran and germ that absorb water slowly, so a wholemeal loaf at 75 per cent handles like a white loaf at 68 per cent and keeps stiffening for the first half hour.
High protein bread flour also takes more water than a soft all-purpose flour. The practical answer is to hold back the last five per cent of water, mix, wait twenty minutes for the flour to hydrate, then decide whether to add it. Humidity matters too: the same formula that behaves in a dry winter kitchen can feel sticky on a humid summer afternoon, which is why bakeries adjust hydration by the day rather than trusting a fixed number.
Worked examples
Everyday sourdough: 500 g flour at 70% with a 100 g liquid levain
350 g total water, 10 g salt, a 200 g levain, and 400 g flour plus 250 g water to weigh at the final mix.
Straight sandwich loaf: 1000 g flour at 62%, no preferment, split into two tins
620 g water, 20 g salt, 10 g yeast and 1650 g of dough, which scales to 825 g per tin.
Ciabatta: 1000 g flour at 80% with a stiff biga using half the flour
800 g total water, 22 g salt, a 750 g biga, and only 500 g flour plus 550 g water left for the final mix.
Pure levain loaf: 800 g flour at 75% with no commercial yeast
600 g water, 16 g salt, no yeast, a 320 g levain and 1416 g of dough in total.
When people use it
- Scaling a bakery formula written in percentages down to one domestic loaf
- Working out what is left to weigh at the final mix once a levain is built
- Raising hydration in controlled steps to open up the crumb
- Converting a stiff biga recipe to a liquid poolish without changing the loaf
- Matching the dough weight per tin so every loaf bakes in the same time
Tips
- Weigh in grams, never cups. A cup of flour varies by up to twenty per cent depending on how it was scooped.
- Add the last five per cent of water after a twenty minute rest, once you can feel how much this flour will take.
- Wholemeal, rye and spelt absorb more water, so lift hydration five to ten points before judging the dough as too stiff.
- Salt slows yeast, so mix it in at the start for a long ferment and hold it back only if you are deliberately autolysing.
- If your levain is 100 per cent hydration, every 100 g of it is 50 g flour and 50 g water, and both belong in the totals.
- Wet your hands rather than flouring the bench when the dough is above 75 per cent, or you will quietly lower the hydration.
What it assumes, and where it stops being accurate
- All percentages are relative to total flour at 100 per cent, which is the standard baker's percentage convention.
- The preferment is assumed to be flour and water only. Salt or starter carry-over in the levain is ignored, which shifts the totals by a gram or two.
- Total dough weight is the raw weight before baking. Loaves lose roughly ten to fifteen per cent of that as steam in the oven.
- Flour absorption is treated as fixed, but real absorption varies with protein content, milling, bran level and kitchen humidity.
- Any starter you discard before feeding is excluded, so enter only the flour actually carried into the dough.
Terms used on this page
- Baker's percentage
- A recipe system where total flour is 100 per cent and every other ingredient is expressed as a percentage of that flour weight.
- Hydration
- Total water divided by total flour, expressed as a percentage. The single best predictor of how a dough will handle.
- Preferment
- A portion of the flour and water fermented ahead of the main mix, such as a levain, biga or poolish.
- Levain
- A sourdough preferment built from a mature starter, usually at 100 per cent hydration.
- Biga
- A stiff Italian preferment, typically around 50 per cent hydration, used for ciabatta and pizza.
- Autolyse
- A rest of flour and water before salt and leaven are added, letting the flour hydrate and the gluten start forming on its own.
Questions people ask
- What exactly is a baker's percentage?
- It is a ratio rather than a share of the whole. Total flour is always set to 100 per cent, and every other ingredient is quoted as a percentage of that flour weight. Because the percentages add to more than 100, the system scales to any batch size without arithmetic: a 2 per cent salt formula means 10 g of salt per 500 g of flour and 20 g per kilogram.
- Do I include the levain flour in the total?
- Yes, and this is the mistake that ruins most first sourdoughs. A 200 g levain at 100 per cent hydration is 100 g of flour and 100 g of water, and both belong in the totals. If you add the full recipe flour on top of it, the real hydration drops by several points and the dough feels stiff for no apparent reason.
- What hydration should I start with?
- Start at 65 per cent with white bread flour. That is high enough for a pleasant crumb and low enough that the dough behaves on the bench. Once shaping feels reliable, move up in five point steps. Sandwich loaves live at 55 to 65 per cent, country sourdough at 70 to 80, and ciabatta and focaccia above 80 where the dough is handled wet in a tub.
- Why does my wholemeal dough feel dry at the same hydration?
- Bran and germ absorb water slowly and keep drinking for the first half hour after mixing, so a wholemeal dough at 75 per cent handles like a white dough at around 68. Add five to ten points of extra water for a wholemeal loaf, mix, then wait twenty minutes before deciding whether it needs more.
- Can I put sugar, butter and milk into the same system?
- Yes, professional formulas quote every enrichment as a percentage of flour, so an 8 per cent sugar brioche means 40 g of sugar per 500 g of flour. Milk counts partly as water, at roughly 87 per cent water by weight, so a dough made with milk is effectively drier than the same number made with water.
- How much dough do I need per loaf tin?
- As a guide, allow about 450 to 500 g of dough for a standard one pound tin and 900 g to a kilogram for a two pound tin. Use the dough per loaf output to divide evenly, because loaves of different weights will not finish baking at the same time and the smaller one dries out.
Use this with
Bread Hydration Calculator answers one part of the question. These pick up where it stops: Recipe Scaler, Cups to Grams Converter, Cup Converter and Meal Cost Calculator.
Where these figures come from
This calculation is jurisdiction-neutral arithmetic. No country-specific rules are applied.
- USDA FoodData Central. Reference composition and caffeine figures for foods and drinks
- King Arthur Baking professional reference. Baker's percentage conventions and flour absorption
- Food Standards Australia New Zealand. Australian and New Zealand food composition and safety advice
Bread Hydration Calculator produces an estimate for general information. It is not financial, tax, medical, legal or engineering advice. read the full disclaimer. Spotted a wrong number? Report it and it gets fixed. The form picks up this calculator and the inputs you used.