DoughRatio Lab / Guide
Baker’s percentage: flour, water and starter
Learn baker’s percentage with a worked sourdough example, a starter breakdown and the difference between hydration and ingredient percentages.
Flour is the reference point
In baker’s percentage, total flour is 100%. Each ingredient’s weight is divided by that flour weight and multiplied by 100. This makes recipes easier to compare and scale. The ingredient percentages usually add to more than 100%, because they are not shares of the finished dough.
A straight dough example
For 1,000 g flour, 680 g water and 20 g salt, the formula is 100% flour, 68% water and 2% salt. Total dough is 1,700 g. Doubling each weight leaves every percentage unchanged. Water percentage is commonly called hydration when the formula’s water sources have been fully accounted for.
Include flour hidden in a preferment
A 100 g starter at 100% hydration brings 50 g flour and 50 g water. If you add it to 500 g flour, 335 g water and 11 g salt, the total flour is 550 g and total water is 385 g. The hydration is 385 ÷ 550 × 100 = 70%, and the salt is 2%. Dividing only 335 by 500 would miss part of the recipe.
Compare like with like
A recipe may express starter weight as a percentage of flour added separately, or describe the prefermented flour as a percentage of total flour. Those are different measurements. Check the author’s convention before comparing two formulas. Our hydration calculator explicitly labels total flour and breaks down the starter.
Make a useful record
Write down flour type, ingredient weights and the ratio convention alongside your dough observations. A repeatable formula is more useful than chasing a single hydration number. This guide covers arithmetic only; it is not a fermentation schedule or a food-safety assessment.
Questions, answered
Does 70% hydration mean 70% of the dough is water?
No. It means 70 g water for every 100 g flour. The water is a smaller share of the total dough weight.
Should salt include starter flour?
This site calculates salt against all flour, including starter flour. If following another recipe, check its stated basis.
Further reading: King Arthur Baking: baker’s percentage reference. The examples and tools on this page use the assumptions stated above.