Baker's Percentage: The Complete Guide
Baker's percentage is the grammar of bread formulas: one convention that makes any recipe readable, comparable and scalable at a glance. It looks intimidating for exactly one paragraph, after which recipe scaling stops being math anxiety and becomes long division. The baker's percentage calculator applies it to any formula, and the hydration guide shows the most famous percentage in action.
The one rule: flour is 100%
Every ingredient is expressed as a percentage of the total flour, which is always 100% - and if the recipe uses several flours, their sum is the 100%. A standard sourdough formula reads: 100% flour, 75% water, 2% salt, 20% starter. Those four numbers completely describe the dough, independent of whether you bake one loaf or twenty: at 1,000 g of flour the dough wants 750 g water, 20 g salt and 200 g starter; at 500 g of flour, exactly half of each.
Reading a formula like a baker
The percentages tell you what kind of dough you are about to make before you touch a bowl. Hydration of 60-65% is a firm, beginner-friendly dough; 70-75% is the open-crumbs standard for sourdough; 80% and beyond is high-hydration territory with sticky handling. Salt near 2% is the norm, and starter between 15-25% sets how fast the bulk goes - the rising time calculator factors the same temperature and culture strength the formula implies.
Scaling: one division, done
To scale a formula to a target dough weight, add up the percentages and divide. For the 100/75/2/20 formula the total is 197%, so 900 g of dough needs 900 / 1.97 ≈ 457 g of flour - and every other ingredient follows from the flour. That division is also how pan sizes get answered: the same formula at 1,600 g of flour makes 3,152 g of dough, enough for two large loaves or a pan's worth of buns.
Why it beats cups
Volume measures shift with how flour is scooped - the same cup can hold 120 g or 150 g of flour depending on packing, which is a 25% formula error before anything else goes wrong. Baker's percentage forces the conversation into grams, and grams are reproducible. It is the same discipline the salt volume vs weight guide argues for on the fermentation side, and it is why every serious bread formula you will ever find is written in percentages.
Questions
Why is flour 100% and not the total dough?
Because flour is the ingredient every other ratio relates to. Setting flour as 100% makes the formula independent of batch size: 70% hydration means 700 g of water for 1,000 g of flour and 350 g for 500 g of flour, with the character of the dough identical. Percent-of-total-dough would change meaning every time the formula changed.
How do I convert a recipe into baker percentages?
Divide each ingredient by the total flour weight and multiply by 100. A dough with 500 g flour, 375 g water, 10 g salt and 100 g starter is 100% flour, 75% water, 2% salt, 20% starter. To go back the other way - percentages to grams - multiply each percentage by the flour weight you want; the calculator does both directions.
How do baker percentages help me scale a recipe to a pan size?
Once the formula is in percentages, the whole recipe scales with one number: the flour weight. Add up the percentages (for 100 + 75 + 2 + 20 that is 197%), decide the dough weight you need, and divide by that total to get the flour - 900 g of dough needs 900 / 1.97, about 457 g of flour. Every other ingredient follows from there.