A bread formula in both directions — percentages to grams and back — with the levain split out and the two hydrations reported separately, because they are two numbers.
Calculator
Try:
1,000 g flour at 70% hydration
1,920 g of dough
the percentages total 192%, and the flour is 52.1% of what comes out of the bowl
Both percentages, side by side
One column sums past 100 and the other sums to exactly 100
Ingredient
Grams
Baker’s %
% of the dough
Flour
1,000
100.0
52.1
Water
700
70.0
36.5
Salt
20
2.0
1.0
Levain or starter
200
20.0
10.4
Oil or fat
0
0.0
0.0
Total
1,920
192.0
100.0
The third column is what a recipe means and the fourth is what is actually in the bowl. Every ingredient’s real share is smaller than its baker’s percentage, by the same factor, because the denominator changed from the flour to the whole dough. That factor here is 1.92.
The levain brings its own flour
Flour inside the levain100 gplus 100 g of water
Dough hydration70.0%counting only what you add to the bowl
Overall hydration72.7%counting the levain’s flour and water too
A levain is not an ingredient like salt — it is flour and water already mixed, and both halves belong in the totals. At 100% hydration it is 50% flour by weight. That is why the number a baker quotes and the number they type into a calculator are usually two different hydrations, and why two recipes at “75%” can behave quite differently.
Salt, both ways round
Against the flour2%how every bread recipe states it
Against the finished dough1.04%what a nutrition panel would report
In this batch20.0 gweigh it; a teaspoon is not a unit of salt
The two figures differ by nearly a factor of two, and both are correct within their own convention. Bread salt sits in a narrow band — below about 1.5% of the flour the dough slackens and ferments too fast, above about 2.5% it tastes salty and the yeast slows — so it is one of the few percentages here that is not a matter of taste alone.
Where this hydration sits
Typical hydration by kind of bread
Bread
Hydration
Note
Bagels and pretzels
50–57%
Stiff enough to be rolled and shaped by hand without flour on the bench.
Sandwich and tin loaves
58–65%
Handles easily, holds a shape, and takes an even crumb.
Everyday sourdough
68–75%
Slack but manageable. Most published sourdough sits here.
Rustic and open-crumb breads
76–85%
Needs folding rather than kneading, and a basket to hold its shape.
Ciabatta and focaccia
80–100%
Barely a dough. Poured and folded rather than shaped.
Hydration is the one percentage that changes how the dough behaves in your hands rather than how it tastes. Ten points is the difference between a dough you knead and one you fold, and it is why a recipe written for one flour can be unworkable with another — a strong bread flour absorbs several points more water than a soft plain flour, and the percentage does not know that.
What this converter covers
Scale from a flour weight or a finished dough weight, see both percentage columns at once, split the levain, and check the hydration against five kinds of bread.
Baker’s percentages to grams, from a flour weight or a target dough weight
Each ingredient’s real share of the finished dough, alongside its baker’s percentage
A levain split into the flour and water it contributes
Dough hydration against overall hydration
Salt against the flour and against the dough
Flour is 100% Two hydrations Scales to any weight Percentages ↔ grams
Free, no signup — exact by definition, not an estimate.
Updated 8 September 2026
At a glance
Formula shown
ingredient grams = flour grams × its percentage ÷ 100 · flour = target ÷ (sum of percentages ÷ 100)
Scenario support
A 190% formula makes 1.9 kg from a kilo of flour · a 100% levain is half flour
Educational estimate
Planning support from the values you enter — not professional advice.
Percentages of the flour
Baker’s percentage is the notation bread recipes are written in everywhere they are written seriously, and it has one rule: the flour is 100%, and everything else is stated as a percentage of it.
So “70% hydration” means 700 g of water per kilo of flour. Two per cent salt means 20 g. It says nothing about how much water is in the dough as a fraction of the dough, and it is not trying to.
The advantage is that a formula scales without arithmetic. The same numbers make one loaf or two hundred, and two recipes can be compared directly whatever quantities they were written for — which is impossible in cups and difficult even in grams.
It also puts the variable that matters where you can see it. Hydration is the single number that decides how a dough handles, and in baker’s percentage it is written on the front of the recipe rather than buried in a list of weights.
Why they add past 100
The one thing that reliably confuses people meeting the notation is that the percentages do not sum to a hundred, and are not supposed to.
A sourdough formula, both ways
Ingredient
Baker’s %
Per kilo of flour
% of the dough
Flour
100
1000 g
52.1
Water
70
700 g
36.5
Levain
20
200 g
10.4
Salt
2
20 g
1.0
Total
192
1920 g
100.0
Read down the second column and nothing adds to a hundred. Read down the fourth and it does, exactly — because that one uses the whole dough as the denominator instead of the flour.
Both are correct and they answer different questions. The baker’s column tells you how to make it; the dough column tells you what it is. The gap between them is the total percentage divided by a hundred — here 1.92, so every real share is a little over half its stated percentage.
Which is where the mistake lands. Someone reading “2% salt” as two per cent of the loaf is reading a figure that is nearer one, and someone converting a nutrition panel back into a formula and forgetting to divide gets a dough that is measurably under-salted.
The levain brings flour
This is the one that catches experienced bakers, and it is why professional formulas are written twice.
A levain, starter, poolish or biga is not an ingredient like salt. It is flour and water that were mixed earlier, and both halves belong in the recipe’s totals. A levain at 100% hydration is exactly half flour by weight; one at 50% is two thirds flour.
So there are two hydrations, and they are different numbers:
1000 g flour, 700 g water, 200 g of 100% levain
Counting
Flour
Water
Hydration
Into the bowl on the day
900 g
600 g
66.7%
Everything, levain included
1000 g
700 g
70.0%
Three and a bit points apart on a modest levain, and much further apart on a recipe built around a large one. Bakers generally quote the overall figure, because it describes the bread, and generally type the dough figure into a calculator, because those are the weights in front of them.
Which is why two recipes both described as “75% hydration” can behave quite differently, and why the professional convention is to write a dough formula and an overall formula side by side rather than picking one.
Scaling to a tin
The everyday use of the notation is running it backwards: you know the dough weight you want, and you need the flour to start from.
Divide the target by the total percentage over a hundred. Flour = target ÷ (total% ÷ 100). For a 900 g loaf at 192%, that is 900 ÷ 1.92, or 469 g of flour — and everything else follows from there.
Two adjustments are worth knowing. Dough loses two to three per cent of its weight in the oven as steam, so a 900 g finished loaf needs about 925 g of dough. And most formulas are written for a batch rather than a loaf, so dividing a formula by the number of pieces is a separate step from scaling it.
For tins specifically, the usual rule is a dough weight per litre of tin volume — roughly 350 to 400 g per litre for a standard tin loaf, less for an enriched dough that rises more. That figure is not a percentage of anything, which is precisely why it is easy to forget when everything else on the page is.
Salt, and the narrow band
Most percentages in a bread formula are a matter of preference. Salt is not, and it is worth understanding why the usable range is as tight as it is.
Salt does three things in a dough beyond tasting of salt: it slows the yeast, it tightens the gluten, and it slows staling. Below about 1.5% of the flour the dough ferments faster than the schedule expects and slackens noticeably. Above about 2.5% the yeast is held back enough to change the timing, and it starts to taste salty.
Almost every bread formula in the world therefore sits between 1.8 and 2.2 per cent, and a recipe outside that band is usually a typo or a different kind of product.
The conversion trap is the one from the section above. Two per cent of the flour is about one per cent of the dough, and a nutrition panel reports the second. A figure carried between the two without dividing is out by nearly a factor of two, in whichever direction the mistake runs.
One last practical note: weigh it. Salts differ enormously in bulk density — a tablespoon of flaky sea salt and a tablespoon of fine table salt differ by roughly half — so a volume measurement of salt is not a measurement at all, and this is the one ingredient where that matters most.
Related calculators
Other kitchen and measurement tools:
CookingCups, spoons and sticks to grams for 16 ingredients — with all five cups, the 20 mL Australian tablespoon, and flour as a range.
Volume to WeightGallons to pounds, cubic yards to tons, litres to kilograms — by substance, with an honest range rather than one invented number.
Cake Pan SizeScale a recipe to the tin you actually have — by area rather than diameter, showing the answer most people get beside the right one.
Oven TemperatureGas marks, °C, °F and fan settings — asking which oven the recipe meant, since the 20 °C offset goes both ways.
Densitykg/m³, lb/ft³, lb/in³ and lb/gal, with specific gravity against any water reference and the API scale that runs backwards.
Brix to SGBrix, Plato, specific gravity and Baumé, plus the refractometer correction — because a refractometer stops measuring sugar the moment fermentation starts.
The first two are where the notation itself comes from, including the professional distinction between a dough formula and an overall formula; the third is why the salt band is narrow enough to be worth stating as a range rather than a preference.
Baker’s percentage and formula basicsKing Arthur Baking Company · verified 2026-09-08 · The convention that flour is set at 100 per cent and every other ingredient stated against it, and the typical hydration ranges for tin loaves, sourdough and very slack doughs
Bread Bakers Guild of AmericaBBGA · verified 2026-09-08 · Professional formula notation, including the distinction between the dough formula and the overall formula when a preferment is used, which is the source of the two hydration figures on this page
AIB International — baking science and food safetyAIB International · verified 2026-09-08 · The functional role of salt in bread dough — its effect on fermentation rate and gluten development — which is why the usable band is narrow rather than a matter of taste alone
Conversion note
This converts a formula between percentages and weights. It does not know your flour, and flour is the variable that matters most: a strong bread flour absorbs several percentage points more water than a soft plain flour, wholemeal more again, and the same recipe at the same stated hydration can be workable with one and unmanageable with another. Ambient temperature, humidity, mixing method and how long the dough rests all change how a given hydration feels and behaves. Fermentation times are not addressed here at all and depend on temperature, the state of the levain and the flour, so no timing follows from any percentage on this page. The salt range given is a working band for ordinary bread, not a dietary recommendation; anyone managing sodium intake should read the nutrition information for what they actually eat rather than a percentage of flour. Weigh ingredients rather than measuring them by volume — that is the reason this notation exists.
Published the Baker's Percentage Calculator: a bread formula converted between percentages and grams in either direction, scaled from a flour weight or from a target dough weight.
Prints BOTH percentage columns side by side -- the baker's percentage against the flour and the ingredient's real share of the finished dough -- because the whole subject is that they are different numbers and only the second sums to a hundred.
Records that a typical formula totals 170 to 200 per cent and the flour is barely half the dough, so every ingredient's real share is smaller than its stated percentage by the same factor.
Splits a levain into the flour and water it contributes, since a preferment is not an ingredient like salt but flour and water already mixed -- a 100 per cent levain is exactly half flour.
Reports the dough hydration and the overall hydration separately, which is why two recipes both described as 75 per cent can behave differently, and why professional formulas are written twice.
Shows salt against the flour and against the dough, which differ by nearly a factor of two, and states the narrow band bread salt actually occupies and why it is functional rather than a matter of taste.
Scales to a target dough weight by dividing by the total percentage, and notes the two adjustments that are not percentages: oven loss of two to three per cent, and dough weight per litre of tin.
Verified by 82 automated cases, asserting that the baker's percentages sum well above a hundred while the shares of the dough sum to exactly a hundred, that percentages and weights round-trip at every flour weight, that a levain at a given hydration is the right fraction of flour and moves the dough hydration in the correct direction, and that a recipe without flour is refused rather than dividing by zero.
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