Baker's percentage and dough hydration calculator

The formula

$$W_i = F \cdot \frac{p_i}{100}$$

Each ingredient’s weight $W_i$ is its baker’s percentage $p_i$ of the flour weight $F$. Flour is always 100%.

Where it comes from

Ordinary recipe percentages divide each ingredient by the total, so changing one ingredient changes every percentage. Bakers instead measure everything against flour, the one ingredient that defines the size of a batch. That makes a formula independent of batch size: 70% water means 70 g of water per 100 g of flour, whether you make one loaf or fifty.

From flour weight. By definition $p_i = 100 \cdot W_i / F$, so rearranging gives each weight directly:

$$W_i = F \cdot \frac{p_i}{100}$$

From total dough weight. Often you know how much dough you want, say three 300 g rolls. The total is flour plus everything else:

$$D = F + \sum_i W_i = F\left(1 + \frac{\sum_i p_i}{100}\right) = F \cdot \frac{P}{100}$$

where $P = 100 + \sum p_i$ is the sum of all percentages including flour’s 100. Solving for flour:

$$F = D \cdot \frac{100}{P}$$

Hydration is simply the water’s baker’s percentage. It’s the single best predictor of how a dough will handle: around 60% is stiff and easy to shape, 70% is typical for crusty bread, and 80% or more is slack and open-crumbed.

Worked example

A lean bread at 70% water, 2% salt and 1% instant yeast totals $P = 173\%$. For 900 g of dough:

$$F = 900 \cdot \frac{100}{173} = 520\ \text{g}, \qquad \text{water} = 520 \cdot 0.70 = 364\ \text{g}$$

Watch out for

• Starter and preferments contain flour and water. For precise hydration, add their flour and water to the totals rather than listing the starter as one ingredient.
• Milk, eggs and butter add water too: milk is about 87% water and eggs about 75%. The calculator’s hydration only counts rows named “water”.
• Expect a little loss. Dough sticks to bowls and benches, so scale up 2–3% if you need an exact final weight.

Last checked November 11, 2026