If you've ever opened a recipe and seen 100%, 65%, 2%, 0.1% next to the ingredients and wondered what those numbers mean, this article is for you. Once you understand baker's percentages, every serious baking book, every dough calculator, and every pizzeria's recipe card becomes legible. You stop following recipes and start reading them.
The one rule
Flour is always 100%. Every other ingredient is expressed as a percentage of the flour weight.
That's it. There is no second rule. The water in your dough is some percentage of the flour weight. The salt is some percentage of the flour weight. The yeast, the olive oil, the malt, the milk: all measured against the flour.
This means baker's percentages don't add up to 100%. A typical sourdough formula might list percentages totalling 175% or more. That isn't a mistake. It's the whole point. The flour is the anchor; everything else floats relative to it.
A worked example
Here is a basic Neapolitan-style pizza dough, written in baker's percentages:
A typical Neapolitan pizza formula. Notice the values don't sum to 100%. They're each measured against the flour.
To turn this into actual ingredient weights, you only need to decide how much flour you want to use. Then you multiply each percentage by that flour weight.
If flour = 1000 g, then:
1 kg of flour produces about 1.65 kg of dough, enough for roughly 6–7 Neapolitan pizzas at 250 g per ball.
Now here is the magic. Suppose tomorrow you want to make a smaller batch, just two pizzas. You don't need a different recipe. You change one number (the flour weight) and everything else recalculates from the same percentages.
If flour = 300 g, then:
Same formula, scaled to 300 g of flour. Two pizza balls of about 250 g.
Same dough. Same ratio of water to flour, salt to flour, yeast to flour. Same final pizza. Just a different starting flour weight.
Why 100%? The formula in formal terms
Mathematically, the percentage of any ingredient is calculated like this:
ingredient % = (ingredient weight / flour weight) × 100
The baker's percentage formula. The denominator is always flour, never total dough weight.
So in the example above: water % = (620 / 1000) × 100 = 62%. Salt % = (30 / 1000) × 100 = 3%. The flour itself is (1000 / 1000) × 100 = 100%, which is why flour is always the anchor.
If a recipe uses two flours (for instance, 80% white flour and 20% whole wheat), then the total flour weight (white + whole wheat combined) is what equals 100%. Every other ingredient is calculated against that combined total.
Why bakers use this instead of cups, ounces, or 'parts'
Three reasons, in order of importance.
- 1.Scaling is one calculation. Want to double the recipe? Double the flour weight. Everything else recalculates automatically because the percentages don't change.
- 2.Comparing recipes is honest. Two recipes might look very different in cups and ounces, but if you convert them to baker's percentages you can see at a glance which one is wetter, saltier, or more yeasted. A 65% hydration sourdough is a 65% hydration sourdough whether you're making one loaf or fifty.
- 3.Communication is precise. When a baker says "I'm running a 75% hydration dough with 2.2% salt and 15% levain," every other serious baker knows exactly what they mean. No translation needed across kitchens, countries, or recipe books.
The most important percentage: hydration
Of all the baker's percentages, hydration (the water-to-flour ratio) is the one that changes the dough's behaviour the most. A 60% hydration dough is firm and easy to shape. An 85% hydration dough is slack, sticky, and behaves more like batter than dough. Same flour, same salt, same yeast, only the hydration changed.
Most everyday breads sit between 60% and 75% hydration. Neapolitan pizza is around 60–65%. A hearty country sourdough might be 75–80%. A high-hydration ciabatta or focaccia can push past 80%. Each step up makes the dough harder to handle but produces a more open, airy crumb if you can manage it.
What about pre-ferments and starters?
Things get slightly more interesting when a recipe uses a pre-ferment: a sourdough levain, a poolish, or a biga. These pre-fermented mixtures contain both flour and water, which means they contribute to the formula's totals.
There are two conventions for handling this. The simple convention is to list the pre-ferment as a single percentage ("20% levain") and not break out its internal flour and water separately. This is fine for casual use. The rigorous convention, used in *Modernist Bread* and most professional bakery formulas, is to calculate the total formula percentage: every gram of flour anywhere in the recipe (including in the pre-ferment) goes into the 100% denominator, and every gram of water (including in the pre-ferment) goes into the hydration calculation.
Both conventions are correct. The first is faster; the second tells you the dough's true hydration. For sourdough specifically, the difference matters: a 75% hydration dough that uses 20% of a 100% hydration levain is actually closer to 77% real hydration once you do the full math.
The dough calculator separates the pre-ferment from the final dough so you can see what belongs in each mix. When you use poolish, biga, or starter, check the preferment section as well as the final dough totals before you weigh ingredients.
Common percentage ranges, for reference
These ranges are starting points, not laws. Every flour, every climate, every kitchen is different, but if your numbers fall well outside these bands, it's worth a second look.
- Salt: 1.8% – 2.2% for most lean doughs. Below 1.5% the dough tastes flat and ferments too fast. Above 2.5% the salt starts to slow the yeast meaningfully.
- Instant yeast: 0.1% – 1.0%. Long cold ferments use the low end. Same-day breads use the high end.
- Sourdough levain: 10% – 30% (when using the simple convention). Higher percentages ferment faster.
- Sugar in lean doughs: 0% – 5%. Above 5% you're in enriched-dough territory and the yeast behaves differently.
- Fat in lean doughs: 0% – 5%. Above this you're heading toward brioche, which has its own rules.
What this changes for you
Once you start thinking in baker's percentages, three things happen. You stop following recipes by rote; you read them and immediately know what kind of dough you're going to get. You can compare any two recipes head-to-head, even if they're written in different units or different languages. And you can scale freely: half a batch, double a batch, batch sized exactly for the dutch oven you own. The math takes care of itself.
Every other article in the Foundations category builds on this. If percentages are the language, the rest of these articles are the vocabulary.