How to use this dough hydration & recipe scaling calculator
- Enter flour and water added outside the starter.
- Enter starter mass and its known water-to-flour hydration percentage.
- Set the desired total flour, including flour inside starter.
- Review hydration and scaled ingredient masses before changing a recipe.
Keep the original input record beside the calculator. All fields have named units, and blank or invalid values produce a check message rather than a useful result. Reset restores the illustrative scenario; it does not choose inputs for your project. Numbers are calculated locally in the current page, without an account or a remote calculation service.
Formula and worked example
With 500 g separately added flour, 325 g separately added water and 100 g of a 100%-hydration starter, total flour is 550 g and total water is 375 g. Hydration is 68.18%. A 1,000 g total-flour target uses a factor of 1.8182, scaling those three ingredient masses to about 909.09 g, 590.91 g and 181.82 g.
The displayed decimals are a presentation choice. Keep the underlying input measurements at the precision you can justify, and avoid treating a rounded output as proof that the inputs were measured with the same accuracy.
Interpretation checks
Count the starter once
The starter field contains both flour and water. Do not also include those amounts in the separately added flour and water fields. Double-counting them changes the denominator and hydration. Keep a starter build record when its feeding history is uncertain; a visual impression of thickness is not a reliable hydration measurement.
Hydration uses flour as the denominator
A 70% dough means 70 g of water for each 100 g of total flour under this model. It does not mean that water is 70% of the final dough mass. Salt, seeds, fats and other ingredients increase dough weight without belonging automatically in this simple water-to-flour ratio.
A scaling factor preserves a formula
Multiplying each represented ingredient by the same factor retains its relationship to total flour. The target field is total flour, not final dough weight or a pan size. If a recipe contains salt or inclusions, scale those separately using the same factor and document any intentional exception rather than leaving an ingredient unchanged accidentally.
The number does not describe handling alone
Flour type, whole-grain content, mixing and other ingredients can change how a dough feels at the same hydration. This tool does not rank flours or predict a proofing schedule. Use the arithmetic to document the formula, then evaluate handling and fermentation through your established baking method.
Keep a comparison record
Start with the question you want the dough hydration & recipe scaling calculator to answer. Save the inputs, named units, source of each value and the output together. Preserve the original before changing an assumption. This makes a second scenario comparable and helps identify whether a different result came from the model, a measurement or a changed source value.
For this topic, the most useful boundary is: hydration uses flour as the denominator. A 70% dough means 70 g of water for each 100 g of total flour under this model. If the calculator cannot represent the condition you need, keep a separate worksheet rather than changing unrelated fields until the result looks plausible. The practical journal guide develops that record in more detail.
Questions and limits
Does 100% starter hydration mean all water?
No. It means equal water and flour masses. A 100 g starter at 100% hydration contains 50 g flour and 50 g water in this model.
Can I use milk instead of the water input?
The tool assumes the entered water is water mass. Milk and other liquids have additional components; this simple model does not calculate their effective hydration.
Does changing hydration set fermentation time?
No. Temperature, starter activity, flour and other factors are outside the calculation.
Model limit: This models flour, water and starter by mass. It does not calculate fermentation time, food safety, salt recommendations or flour absorption, and it does not treat other wet ingredients as pure water.
References and corrections
References are provided for context, not as endorsements. The tool does not import measurements, prices, rates or requirements from them. Check the exact source relevant to your own input before making a decision. The editorial policy explains our approach, and the contact page accepts reproducible calculation issues without private records.