Dough Hydration Calculator

How to use the dough hydration calculator

1. Choose Find hydration to check known flour and water weights, or Water for a target to calculate water from flour and your chosen percentage.
2. Choose the weight unit used by your recipe, then enter the separately added flour and the water or target. Keep every weight in that same unit; the unit selector labels your numbers rather than converting them.
3. If you are adding a flour-and-water starter or preferment, select Include starter and enter its weight and known hydration. Do not also include its flour or water in the main fields.
4. Read the primary result and, when starter is included, the compact overall flour and water context. Open calculation details or copy the current qualified summary if useful.

Enough functionality for the usual recipe questions

• Two clearly named jobs: find hydration from weights or find separately added water for a target.
• One recipe-wide choice of grams, kilograms, ounces or pounds, with no mixed-unit ingredient entry.
• Optional starter or preferment weight and actual hydration, including an explicit equal-weight 100% choice.
• A clear diagnostic when starter water makes a target impossible without changing the inputs, instead of silently returning zero.
• Current qualified Copy, compact starter totals and closed calculation details without a full recipe dashboard.

When this calculation is useful

• Checking the water-to-flour percentage of a bread or pizza dough from weights you already know.
• Working out water for a target percentage stated in your own recipe.
• Including the flour and water already present in a known flour-and-water sourdough starter or preferment.
• Checking a blended-flour recipe after adding the separately added flour weights together.

Understanding hydration without double-counting

Hydration here is total water weight divided by total flour weight, multiplied by 100. It is not water as a percentage of the whole dough, so salt and other ingredients do not become part of the flour denominator.

The main flour and water fields are ingredients added outside the starter. When starter is included, the tool adds its modeled flour and water once. If your recipe already gives overall flour and water totals, leave starter inclusion off and enter those totals instead.

For a flour-and-water starter with weight S and hydration h%, its flour is 100S divided by 100 + h, and its water is the remainder. Use the starter's known percentage; 100% means equal ingredient weights, not that every starter or feeding schedule has that hydration.

For a target H%, the separately added water is overall flour multiplied by H divided by 100, minus the starter's water. A negative result means the supplied starter already exceeds the target's water allowance; the tool reports that conflict before any rounding.

All weights must use one selected unit. Changing g to kg keeps the entered numbers, so it describes a larger physical recipe, not the same recipe converted to kg. The hydration percentage is unchanged because both ingredient weights use the same basis.

Worked dough and starter calculations

500 g of separately added flour and 350 g of water, with starter inclusion off, give exactly 70% hydration.

With 500 g flour, 350 g water and 100 g of a 100% flour-and-water starter, the overall flour is 550 g and water is 400 g. The displayed hydration is About 72.73%.

With 500 g separately added flour, a 70% target and 100 g starter at 100% hydration, the target overall water is 385 g. The starter supplies 50 g, so weigh 335 g water separately.

With 500 g flour, 350 g water and 150 g starter at 50% hydration, the modeled starter has 100 g flour and 50 g water. The overall 400 g water divided by 600 g flour gives About 66.67%.

With 100 g separately added flour, a 50% target and 400 g starter at 100% hydration, the starter supplies 200 g water while the target allows 150 g overall. There is no nonnegative separately added water amount; the calculator does not turn the negative arithmetic into a zero result.

What the result does not decide

This tool models weighed flour and water, including one optional starter treated as flour and water only. It does not infer water inside milk, eggs, fruit, oil or other ingredients, or account for starter additives and fermentation mass changes.

It does not select an ideal hydration, predict flour absorption, dough feel, crumb or fermentation time, or build a recipe with salt, yeast, temperatures, loaf sizes or servings. The same arithmetic percentage does not guarantee the same baking behavior.

Input weights are limited to 10,000 of the selected unit with two decimal places; added flour and included starter must be positive, while separately added water can be zero. Target hydration accepts 0–300%, and included starter hydration 0.01–1000%. These are software limits, not baking recommendations. Derived water can exceed the input-weight cap.

Recipe numbers stay in this tool

The calculation uses your active recipe numbers in browser memory. It does not upload a recipe, store a setup or put ingredient amounts in the URL; Copy writes a qualified summary only when requested.

The surrounding website still loads its ordinary resources and services. Local calculation is not a claim that the whole page is network-free.