Baker's Percentage Calculator

Background.

Baker's percentage is the notation professional bakeries, flour millers and federal food regulations all use to describe a dough, and it has exactly one rule: the total flour weight is 100%, and every other ingredient is written as a percentage of that flour weight. King Arthur Baking states it plainly — "the total weight of flour is always treated as 100%" and all other ingredients are percentages relative to it. This calculator applies that rule in all three directions at once. Give it ingredient weights and it returns the percentages. Give it a flour weight and a set of percentages and it returns the weights. Give it a target dough weight and a set of percentages and it works backwards to the flour, which is the direction a baker actually needs when the requirement is "two 900 gram loaves" rather than "start with a kilo of flour".

The first thing that trips people up is that the percentages add to more than 100%. That is not an error; it is the point. Because the denominator is flour rather than the whole dough, a straightforward lean bread comes out at roughly 169% and an enriched brioche can pass 250%. The sum is called the total formula percentage and it is directly useful: multiply the flour weight by it and divide by 100 and you have the dough weight, and the same relation run backwards is how this page sizes a batch from a target weight. King Arthur's own worked example scales a 3 kilogram ciabatta batch exactly this way, and this calculator reproduces their published figures to the gram.

The second thing that trips people up is hydration. Hydration is simply the water row of the same table — water weight divided by flour weight — and it is the single number that predicts how a dough will feel in the hands. King Arthur reports that a dough in the 55% to 65% range "will likely feel firm or even stiff", that 75% to 85% "will likely be slack or sticky", and that high hydration means "doughs that are often in excess of 80% hydration". This page classifies your hydration against those published edges — 55, 65, 75 and 80 — and it does so on the unrounded value, so a dough at 54.9999% is reported as very stiff rather than being rounded up into the next band.

Two scope limits belong right beside the answer rather than buried in an FAQ. First, the leaven on this page is an opaque ingredient. If you feed it 100 grams of sourdough starter, it reports 100 grams of leaven as a percentage of flour and stops there — it does not open the starter up and count the flour and water inside it. That decomposition changes the flour total, changes the water total, and therefore changes the hydration figure, which is why it lives on the separate Sourdough Calculator. If you bake with commercial yeast, that distinction never matters and this page is the whole answer. Second, every input is a mass. Baker's percentage is undefined on volumes, because a cup of flour is not a fixed quantity of flour: King Arthur's chart puts a spooned and levelled cup of all-purpose flour at 120 grams, and a cup scooped straight from the bag can be twenty percent heavier. A calculator that accepted cups would be reporting a hydration figure with a twenty-percent error bar hidden inside it.

One useful consequence of the notation is that the percentages are dimensionless. Grams divided by grams cancels, so the identical percentage set describes the identical dough whether you weigh in grams, ounces or kilograms — provided you use one unit throughout the formula and do not mix them. That is why professional formulas travel across countries unchanged while volume recipes do not, and it is why a 500 gram home batch and a 500 kilogram plant batch can share one specification sheet.

Below the calculator you will find the arithmetic written out in full, the rounding contract, King Arthur's basic formula worked step by step, the ciabatta scale-up that tests the inverse direction, and answers to the questions this notation actually raises: why the total exceeds 100%, whether oil counts as hydration, what to do about a sourdough starter, how to convert a cup-measure family recipe, and why salt percentage is so sensitive to which salt you own.

What is baker's percentage calculator?

Baker's percentage — also called baker's math or baker's percent — is a way of writing a recipe in which the total weight of flour is defined as 100% and every other ingredient is expressed as 100 x its own weight divided by that flour weight. A lean bread might be written as flour 100%, water 66%, salt 2%, yeast 1.2%. The notation is not a home-baking curiosity: 21 CFR 136.110, the U.S. federal standard of identity for bread, rolls and buns, writes every optional-ingredient limit the same way — nonwheat flours at "not more than 3 parts for each 100 parts by weight of flour used", monocalcium phosphate at 0.75 part, dough conditioners at 0.5 part. Yeast manufacturers dose the same way: Lesaffre specifies Saf-instant Red at "1-3% based on flour weight".

Two derived figures matter. Hydration is the water row, and it predicts dough handling more reliably than any other single number. Total formula percentage is the sum of every row including the 100% flour row, and it converts between a flour weight and a dough weight in one multiplication.

The range of validity is any formula whose ingredients are weighed and whose flour is identifiable. It is exact arithmetic, not an estimate, so there is no error term. What it does not model is process: mixing, fermentation time, dough temperature, oven spring and baking loss are all outside the notation. A dough at 75% hydration in a strong bread flour behaves differently from the same 75% in a soft pastry flour, because hydration is a ratio of weights and says nothing about how much water the protein and starch in a particular flour can actually hold.

It is also undefined on volume measurements, and it deliberately treats a leaven as one opaque ingredient rather than as the flour-and-water mixture it may actually be.

How to use this calculator.

1. 01Choose the direction. Pick 'Ingredient weights' when you are converting a recipe you already have into percentages. Pick 'A flour weight + percentages' when you are following a published formula. Pick 'A target dough weight + percentages' when you know the finished dough weight you want and need the calculator to solve backwards for the flour.
2. 02Enter the total flour weight in grams — every flour added together, white plus whole wheat plus rye. This is the 100% reference and it is the denominator of every percentage on the page, so it is the one field that cannot be zero.
3. 03Enter the water or liquid weight. Milk, beer and juice count as liquid; oil and butter do not, because King Arthur's baker's-math convention keeps fats out of hydration. Put fats in the Other field instead.
4. 04Enter salt and leaven by weight rather than by spoon. A tablespoon of table salt is 18 g and a tablespoon of Diamond Crystal kosher salt is 8 g, so a spoon measure can more than double your salt percentage without you noticing.
5. 05Put everything else — sugar, fat, eggs, seeds, inclusions — into the single Other field. It is reported as one combined percentage.
6. 06Set the piece count to the number of loaves, rolls or pizza balls you want. It divides the dough weight and changes nothing else.
7. 07Read the hydration band beside the headline figure. It is classified against percentages King Arthur publishes, and it is decided on the unrounded value, so a dough sitting a fraction below an edge is not promoted into the band above it.
8. 08If your leaven is a sourdough starter, stop here and use the Sourdough Calculator instead. This page does not count the flour and water inside a starter, so the hydration figure it reports for a sourdough formula is the mix hydration, not the overall hydration.

The formula.

There is one equation and three ways to read it.

Forward, from weights to percentages: Pᵢ = 100 x Wᵢ / W_flour. King Arthur's published basic formula is flour 500 g, water 330 g, salt 10 g, yeast 6 g. Water gives 100 x 330 / 500 = 66%, salt gives 100 x 10 / 500 = 2%, yeast gives 100 x 6 / 500 = 1.2%. Those are exactly the percentages King Arthur prints beside those weights, which is why this formula set is used as the page's worked example rather than a number invented here.

Backward, from a flour weight to weights: Wᵢ = W_flour x Pᵢ / 100. Nothing subtle happens in this direction.

Backward again, from a target dough weight: the total formula percentage T = 100 + h + s + l + o, and the dough weight D = W_flour x T / 100, so W_flour = D x 100 / T. T can never be less than 100 because the flour row contributes 100 on its own, so there is no division by zero anywhere in this page. King Arthur's ciabatta example is the test of this direction: a 3,000 g batch at flour 100%, water 82%, salt 2%, yeast 0.5%, oil 5% gives T = 189.5%, so the flour is 3,000 x 100 / 189.5 = 1,583.11 g, the water is 1,298.15 g, the salt 31.66 g, the yeast 7.92 g and the oil 79.16 g. King Arthur publishes approximately 1,583 g, 1,298 g, 32 g, 8 g and 79 g for the same batch. Every figure agrees.

Rounding stage. Nothing is rounded at an intermediate step. Every quantity is carried in arbitrary-precision decimal arithmetic and rounded exactly once, at the point the result leaves the calculator, to ten decimal places. This matters most in the third direction: if the flour weight were rounded to the nearest gram before the other rows were derived from it, the five rows would no longer sum to the dough weight you asked for. Because it is not, they do — the ciabatta example sums back to 3,000.00 g rather than to 2,999.6 g.

Classification stage. One output classifies: the hydration band. The scalar that drives it is the hydration percentage, read unrounded, before the ten-decimal-place conversion. The four edges — 55, 65, 75 and 80 — are the figures King Arthur publishes, and each is tested immediately below, exactly at, and immediately above. A dough at 54.9999% hydration is therefore reported as very stiff even though the label prints the rounded '55%', which is the specific failure this rule exists to prevent.

One convention worth stating because sources differ. King Arthur's baker's-math guidance says fats such as oil "don't count toward hydration percentages", and this page follows that: hydration is the water and water-like liquid row only, and fats belong in Other. Some other writers fold every liquid, including oil, into a single hydration figure. Neither is wrong — they define a different numerator — but a page that made the choice silently would produce a hydration figure a reader could not reconcile with their source. If you are comparing this calculator against a formula that counts oil as hydration, add the oil percentage to the hydration figure here before you compare.

A worked example.

Frequently asked questions.

References& sources.

1. [1]King Arthur Baking Company. "What is baker's math, and how can I use it in my everyday bread baking?" Blog post dated 28 April 2022; retrieved 30 July 2026. The primary source for the page's core rule — "the total weight of flour is always treated as 100%" and all other ingredients are percentages of it — for the basic formula table used as the worked example (Flour 100% / 500 g, Water 66% / 330 g, Salt 2% / 10 g, Yeast 1.2% / 6 g), for the statement that fats such as oil do not count toward hydration, and for the 3 kg ciabatta scale-up at 100 / 82 / 2 / 0.5 / 5 that yields approximately 1,583 g flour, 1,298 g water, 32 g salt, 8 g yeast and 79 g oil. Independence: primary. Access: open.
2. [2]King Arthur Baking Company. "Hydration in bread dough, explained." Blog post dated 11 January 2023; retrieved 30 July 2026. The source of the hydration definition (water weight divided by flour weight, as a percentage) and of all four band edges this calculator classifies against: "a recipe hydrated in the 55% to 65% range will likely feel firm or even stiff"; "a hydration percentage in the 75% to 85% range … will likely be slack or sticky"; "High hydration refers to doughs that are often in excess of 80% hydration". Also the source of the rule that a starter's own flour and water count toward the totals — "everything that comprises the loaf you place in the oven should be considered as part of the loaf" — which is why this page defers sourdough formulas to the Sourdough Calculator. Independence: primary. Access: open.
3. [3]King Arthur Baking Company. Ingredient Weight Chart, current revision; retrieved 30 July 2026. Source of the gram-per-volume figures quoted on this page for readers converting a cup-measure recipe: all-purpose flour 1 cup = 120 g, bread flour 1 cup = 120 g, self-rising flour 1 cup = 113 g, granulated sugar 1 cup = 198 g, water 1 cup = 227 g, table salt 1 tablespoon = 18 g, Morton's kosher salt 1 tablespoon = 16 g, Diamond Crystal kosher salt 1 tablespoon = 8 g, instant yeast 1 tablespoon = 9 g. Independence: primary. Access: open.
4. [4]U.S. Government Publishing Office / U.S. Food and Drug Administration. 21 CFR § 136.110, "Bread, rolls, and buns", 2023 annual edition; retrieved 30 July 2026. Cited for the point that baker's percentage is the notation of federal law and not only of recipe writing: every optional-ingredient limit in the standard of identity is expressed as parts "for each 100 parts by weight of flour used" — nonwheat flours, meals, grits and starches at not more than 3 parts, ground dehulled soybeans at 0.5 part, yeast nutrients and calcium salts at 0.25 part, monocalcium phosphate at 0.75 part, and dough strengtheners and conditioners at 0.5 part. Independence: primary. Access: open.
5. [5]Lesaffre. Saf-instant Red product data page, current revision; retrieved 30 July 2026. Cited as an industrial authority dosing its own product in baker's percentage independently of any recipe publisher: "Use 1-3% based on flour weight". This is the figure the calculator's leaven-percentage hint quotes as the ordinary commercial-yeast range. Independence: primary. Access: open.
6. [6]National Institute of Standards and Technology. NIST Special Publication 811, 2008 edition — Guide for the Use of the International System of Units (SI). Table B.8, avoirdupois mass factors: the international pound is exactly 453.59237 g and the avoirdupois ounce exactly 28.349523125 g. Cited as the basis for the page's statement that a baker's percentage is dimensionless — grams divided by grams and ounces divided by ounces give the same ratio — and therefore that a formula is portable across mass units provided one unit is used throughout. Independence: primary. Access: open.