Baker's Percentage Calculator

How this is calculated

BAKER'S PERCENTAGE IS A RATIO, NOT A PROPORTION. Flour is always 100%, and every other ingredient is expressed as a percentage OF THE FLOUR WEIGHT rather than of the whole dough. That is why the percentages add up to more than 100 and nothing is wrong. It exists so a formula scales to any batch size without re-deriving anything, and so two recipes can be compared directly however much dough each makes. ⚠️ A SOURDOUGH STARTER IS FLOUR AND WATER, AND BOTH COUNT. This is the step that goes wrong most often. A 100% hydration starter is half flour and half water by weight, so 100 g of it adds 50 g of flour and 50 g of water to the dough. If you ignore that and just add your target water on top, the real hydration ends up well above what you intended and the dough is slacker than expected. This calculator adds the starter's flour to the flour total and subtracts its water from the water you still need to add. It also shows what you WOULD have ended up at by pouring the full target water on top of the starter, so the size of the mistake is visible: at 70% target with a 20% starter, ignoring it lands you at 79.1%. THE PERCENTAGES ARE INPUTS, NOT RECOMMENDATIONS. The defaults are ordinary starting points, not an optimum this tool is claiming - bread is far too varied for that. A stiff bagel dough and a ciabatta are both correct at wildly different hydrations, and salt, yeast and starter quantities move with the flour, the ambient temperature and how long you intend to ferment. Use your own recipe's figures; the tool does the arithmetic, not the judgement. SALT AND YEAST ARE CALCULATED ON TOTAL FLOUR, including the flour inside the starter. That is the usual convention and it is the one that keeps the seasoning consistent when you change the amount of starter. If your recipe states salt as a percentage of the flour you scoop out of the bag only, its figure will be slightly lower than this one. ⚠️ A DASH IN "WATER TO ADD" MEANS THE STARTER ALREADY BRINGS MORE WATER THAN YOUR TARGET HYDRATION ALLOWS. It is not an error in the tool - it is telling you the combination is impossible. Either raise the target hydration or use less starter. Showing a negative weight of water would be worse than showing nothing. WEIGH, DO NOT MEASURE BY VOLUME. A cup of flour varies by around 20% depending on whether it was scooped or spooned and levelled, which is a larger error than the difference between two hydrations you would consider distinct. Baker's percentage only means anything on a scale, and this is the main reason serious bread recipes are written in grams. THIS DOES NOT MODEL FERMENTATION. It converts ratios to weights. How long to prove, at what temperature, and when the dough is ready are judgement calls that depend on your kitchen and your flour, and no arithmetic here substitutes for looking at the dough.

Common questions

Why do the percentages add up to more than 100?

Because they are not shares of the dough - they are ratios to the flour. Flour is defined as 100% and everything else is measured against it, so a dough at 70% hydration with 2% salt totals 172% and nothing is wrong. The point of expressing it this way is that the formula scales to any batch size without re-deriving anything, and two recipes can be compared directly even if one makes a single loaf and the other makes forty.

Why does my starter change the water?

Because a starter is flour and water, and both of them are already in your dough before you add anything. A 100% hydration starter is half flour and half water by weight, so 200 g of it brings 100 g of flour and 100 g of water. If you add your full target water on top of that, you have overshot the hydration and the dough will be slacker than you intended. This calculator adds the starter's flour to the flour total and subtracts its water from the water you still need, so the figure it gives you is the water to actually pour in.

Is 2% salt right?

It is an ordinary starting point, not a rule this tool is asserting - which is why it is an input rather than a constant. Salt controls fermentation speed as well as flavour, so the right figure moves with how long you intend to ferment and at what temperature, and some breads are deliberately well outside the usual range. Use whatever your recipe states. Note that this tool calculates salt on TOTAL flour including the starter's, so if your recipe means only the flour from the bag, its percentage will read slightly lower than this one.

Why is 'water to add' sometimes blank?

Because the starter on its own is already bringing more water than your target hydration allows, so the water you would need to add is negative - which is to say the combination is impossible as entered. The fix is either a higher target hydration or less starter. It shows a dash rather than a negative weight because there is no such thing as adding minus fifty grams of water, and a negative number there would just look like a bug.

Can I use this for a poolish or biga?

Yes - that is what the starter fields are for. A poolish is typically 100% hydration, so leave the starter hydration at 100. A biga is stiffer, usually somewhere around 50 to 60%, so set it accordingly and the flour and water split will follow. The arithmetic does not care whether the preferment is leavened with commercial yeast or with a sourdough culture; it only cares how much flour and water are inside it.

Do I need to weigh everything?

For this to mean anything, yes. A cup of flour varies by roughly 20% depending on whether it was scooped from the bag or spooned in and levelled, and that swing is larger than the difference between two hydrations you would treat as meaningfully different. Baker's percentage is a weight ratio and it only works on a scale. This is the main reason serious bread recipes are written in grams, and a cheap digital scale removes more variability from your baking than almost anything else you could buy.

Does it tell me how long to prove?

No, deliberately. It converts ratios into weights, which is arithmetic. How long to ferment, at what temperature, and when the dough is actually ready are judgement calls that depend on your flour, your kitchen and your starter's vigour on the day - and the honest answer is to watch the dough rather than the clock. A number here would look authoritative and be wrong in most kitchens.

Take it further with AI

Copy this into ChatGPT or Claude with your own numbers filled in. It hands over the figures this calculator worked out, so the answer is built on real arithmetic instead of a guess.

I used the Baker's Percentage Calculator at https://www.bfcbrilliance.com/tools/bread-baker-percentage-calculator.

What I entered:
- Flour you are adding (g): ___
- Target hydration (%): ___
- Salt (%): ___
- Yeast (%): ___
- Starter or preferment (%): ___
- Starter hydration (%): ___

What it calculated:
- Water to add: ___
- Total flour (with the starter's): ___
- Starter to weigh out: ___
- Salt: ___
- Yeast: ___

Use those figures as given — they are already worked out, so please don't recalculate or estimate your own. Help me turn them into a plan: what to buy or do, in what order, roughly what it should cost, and the mistakes people most often make with this job.

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