What is dough hydration and why does it matter?

Hydration is the ratio of total water to total flour expressed as a percentage. It directly controls the texture of the finished bread. Lower hydrations (60–68%) produce tight, chewy crumbs like bagels; medium hydrations (70–78%) give a classic open sourdough crumb; and very high hydrations (85%+) produce the large irregular holes typical of ciabatta or focaccia. Higher hydration also increases extensibility, so the dough can expand more during fermentation and oven spring, but it becomes progressively stickier and harder to shape.

What are baker's percentages?

Baker's math expresses every ingredient as a fraction of the total flour weight, not of the total dough weight. Flour is always 100%. Water at 75% means 75 g of water for every 100 g of flour. This convention makes scaling recipes trivially easy — double or halve the flour number and every other figure scales with it — and lets bakers compare recipes regardless of batch size.

Why do I need to enter my starter hydration separately?

A sourdough starter is itself a mixture of flour and water. A 100% hydration starter fed equal weights of flour and water contains exactly 50% flour and 50% water. If you ignore the starter's internal composition, your actual dough hydration will be wrong, sometimes by several percentage points on a typical home loaf. This calculator splits the starter into its flour and water fractions before computing totals.

What hydration should a beginner start with?

Most baking teachers recommend 70–75% for a first sourdough loaf. The dough is workable with wet hands, holds its shape through shaping and scoring, and still produces an open crumb. Once you are comfortable with dough handling, push to 78–82% for a more open texture. Doughs above 85% almost always require stretch-and-fold technique in the bowl rather than conventional kneading.

What is a typical starter inoculation percentage?

Inoculation (starter as a percentage of total flour) usually falls between 10% and 30% for a same-day or overnight schedule. A 10–15% inoculation produces a slow 12–16-hour cold-retard loaf; 20–25% suits an 8–10-hour ambient ferment at 24 °C; 30%+ accelerates fermentation to 4–6 hours, useful in cooler kitchens. Raising inoculation also increases acetic acid tang, so dialling it in is partly a flavour decision.

Does salt affect hydration?

Salt is not counted in the hydration percentage because it contributes neither flour nor water. Typical sourdough salt sits at 1.8–2.2% of total flour weight. Salt does tighten the gluten network (strengthens the dough) and slows fermentation slightly, but its weight has no bearing on how wet or dry the dough feels to work with.

What is the Sourdough Hydration & Baker's Percentage Calculator?

Free sourdough calculator. Enter your flour, water, starter weight and starter hydration to get exact dough hydration, baker's percentages and full ingredient breakdown. 100% client-side. It runs free in your browser on Gera Tools, with nothing uploaded.

Sourdough Hydration & Baker's Percentage Calculator

Name: Sourdough Hydration & Baker's Percentage Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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A sourdough hydration calculator that computes your exact dough hydration, every baker’s percentage, and the precise flour and water contribution from your starter — so you can scale, adjust, and compare recipes with confidence.

How it works

Bread bakers measure everything relative to total flour = 100% — a convention called baker’s percentages (baker’s math). Every other ingredient is expressed as a fraction of that total flour. The tricky part with sourdough is that the levain or starter is itself a mixture of flour and water, so you cannot simply add its weight to the water column; you must first split it into its two components.

Starter split

A starter of weight W maintained at hydration H (in %) contains:

starter flour = W ÷ (1 + H/100) starter water = W − starter flour

For a 100 g starter at 100% hydration this yields 50 g flour and 50 g water. For a stiff 50%-hydration starter the same 100 g contains about 67 g flour and 33 g water — a significant difference that changes your dough hydration by several points.

Dough hydration

Once the starter is split:

total flour = main flour + starter flour total water = main water + starter water hydration (%) = total water ÷ total flour × 100

Salt is included in the dough total weight but is not part of the hydration formula.

Worked example

A classic country loaf uses 450 g bread flour, 310 g water, 100 g starter at 100% hydration, and 9 g salt.

Starter split: 100 ÷ (1 + 1.00) = 50 g flour, 100 − 50 = 50 g water
Total flour: 450 + 50 = 500 g (this becomes 100% in baker’s math)
Total water: 310 + 50 = 360 g
Hydration: 360 ÷ 500 × 100 = 72%
Salt: 9 ÷ 500 × 100 = 1.8% — a classic ratio
Starter inoculation: 100 ÷ 500 × 100 = 20% — suits an 8–10-hour ambient rise

The final dough weighs 500 + 360 + 9 = 869 g, enough for one large boule.

Style	Flour (g)	Water (g)	Starter (g)	Hydration
Stiff levain	480	265	80	~65%
Country loaf	450	310	100	~72%
Open-crumb batard	430	330	100	~78%
Ciabatta	430	355	100	~90%

All examples assume a 100% hydration starter.

Formula note

The calculator uses the standard baker’s math convention where total flour is the reference weight (100%), not total dough weight. This is the norm in professional bakeries and most published bread recipes. Hydration and inoculation percentages can exceed 100% — this is mathematically valid and expected at the extremes (a focaccia at 110% hydration is wetter than it is floury, but the formula is unchanged).

Every calculation runs entirely in your browser; no weights or recipe data are ever uploaded to a server.