Bread Hydration Calculator

Bread Hydration Calculator: calculate bread hydration for cooking and nutrition. Practical tips and worked examples.

The Sourdough Hydration Calculator works out the true hydration percentage of your dough using baker's percentages, accounting for the flour and water already present in your starter. It categorises your dough from stiff (under 65%) to expert (above 85%), calculates salt percentage, total dough weight, and scales all quantities proportionally when baking multiple loaves. Use Recipe Scale Calculator for general recipe scaling, or Ingredient Weight Calculator for nutritional calculations based on your bread ingredients.

In professional baking, the baker's percentage system expresses all ingredients as a percentage of total flour weight, making recipes infinitely scalable. A 100% hydration starter (also called a levain) contains equal parts flour and water by weight — this is the most common starter hydration for home bakers. King Arthur Flour's research shows that doughs above 75% hydration require autolyse (resting flour and water together before adding starter and salt) to develop gluten structure. The Tartine Country Bread method, which popularised high-hydration artisan sourdough, typically works at 75–85% hydration.

Enter the Flour (g) — this is the additional flour in your recipe, not including flour inside your starter.
Enter the Water (g) — again, excluding water inside your starter.
Enter your Starter (g) total weight and its hydration % — a 100% hydration starter means 50g flour + 50g water per 100g of starter.
Enter Salt (g) — 1.8–2.2% of total flour is the professional range.
Set Loaves to scale the recipe; all ingredient weights update proportionally.

Baker's percentage hydration formula

Starter flour = Starter weight ÷ (1 + Starter hydration ÷ 100). Starter water = Starter weight − Starter flour. These split the starter into its constituent flour and water components.

Total flour = Recipe flour + Starter flour. Total water = Recipe water + Starter water. Hydration % = (Total water ÷ Total flour) × 100.

Worked example: 500g flour + 375g water + 100g starter at 100% hydration + 10g salt. Starter flour = 100 ÷ 2 = 50g. Starter water = 50g. Total flour = 550g. Total water = 425g. Hydration = 425 ÷ 550 × 100 = 77.3% — classified as "Intermediate — open crumb". Salt % = 10 ÷ 550 × 100 = 1.82% ✓.

Understanding your dough hydration

Hydration level and dough category

The hydration percentage determines handling difficulty and crumb structure. Stiff doughs (below 65%) are dense and easy to shape — ideal for bagels, pasta, and enriched doughs. Beginner sourdough (65–70%) holds its shape well and is forgiving for new bakers. Intermediate (70–78%) produces a more open crumb and requires good shaping technique. Advanced (78–85%) needs skilled hands and proper bread tins to hold shape. Expert (above 85%) is extremely slack — best attempted with a long, cold fermentation and professional equipment.

The salt percentage should sit between 1.8% and 2.2% of total flour weight. Below 1.8%, bread tastes flat and ferments too quickly (salt slows yeast and bacteria activity). Above 2.2%, the dough ferments very slowly and the bread can taste unpleasantly salty. The 2% benchmark (11g per 550g total flour) is the standard used by most artisan bakeries.

Food tips and best practices

Autolyse for high-hydration doughs: mix flour and water and rest for 30–60 minutes before adding starter and salt. This hydrates the flour and reduces mixing time.
Use stretch-and-fold instead of kneading for wet doughs: 4 sets of folds at 30-minute intervals during bulk fermentation builds structure without degassing.
Keep a baking journal: note the hydration, bulk fermentation time, ambient temperature, and oven spring for every bake to identify which variables affect your outcome.
Scale by weight, not volume: flour especially is highly variable by volume — a cup of flour can weigh anywhere from 120g to 160g depending on how it is measured.
Starter health is more important than hydration: a sluggish starter will produce flat bread regardless of hydration level — feed it regularly and use it at peak activity (doubled in size, domed surface, sour smell).
Cold retard (overnight in the fridge after shaping) develops flavour through a longer, cooler fermentation and makes scoring easier on a firm, cold loaf.

Baker's percentage: all ingredients expressed as a % of flour weight — 100% flour, typically 60–85% water, 1.8–2.2% salt, 15–20% starter. [King Arthur Flour]
Tartine Country Bread hydration: 75–80% — the method that popularised high-hydration artisan sourdough globally. [Tartine Bread, Chad Robertson]
Autolyse effect: resting flour and water before mixing reduces required mixing time by 30–50% and improves gluten development at hydrations above 75%. [SFBI research]
100% hydration starter: equal flour and water by weight — the default for most home bakers; stiff starters (50–60%) are favoured in some Italian traditions. [King Arthur Flour]

Common mistakes to avoid

Not accounting for starter hydration — treating all starter as 100% hydration when yours is 80% will give an inaccurate total water calculation.
Adding all the flour to the hydration calculation without separating out starter flour — this underestimates total flour and overstates hydration.
Assuming higher hydration always means better bread — at 85%+ without the right technique, the dough will spread flat rather than spring upward.
Using cold tap water in winter — water temperature affects fermentation speed dramatically; aim for 25–27°C dough temperature for consistent results.

This calculator is based on the baker's percentage system used in professional baking. Results are for recipe planning purposes only. This tool does not constitute nutritional, dietary, or medical advice. For allergen information and nutritional analysis of baked goods, consult a qualified food scientist or registered dietitian.