Bread Dough Hydration Calculator
Find your dough's true hydration — total water over total flour — counting the flour and water hidden inside a starter or preferment, plus wet add-ins like milk and eggs. The number that actually predicts how your dough handles.
Just the flour and water you add directly — starter and preferment go below.
A 100% starter is equal flour and water; a stiff levain might be 50–60%.
Advanced: preferment & wet add-in
Formula & how it works
A starter or preferment of amount A at hydration H splits into flour = A ÷ (1 + H/100) and water = A − flour.
True hydration = total water ÷ total flour × 100, where totals add the main flour and water, the split starter and preferment, and each wet add-in's water (amount × water% ÷ 100).
Worked example
900 g flour and 630 g water look like 70% hydration. Add 200 g of 100% starter — that's 100 g flour and 100 g water — and the totals become 1,000 g flour and 730 g water, so true hydration is 73%. Stir in 100 g of milk at 88% water and it climbs to about 81.8%. The starter and the milk both quietly wet the dough.
Getting hydration right
Simple hydration hides the starter
Reading water divided by added flour ignores everything living in your levain, and at meaningful inoculations that gap is real — several points of hydration that change how the dough feels and proofs. Splitting the starter by its own hydration and rolling it into the totals gives the number that actually predicts stickiness, spread, and crumb.
Preferments shift the balance
A poolish is typically 100% hydration and a biga much stiffer, so the same weight of each contributes very different amounts of water. If your formula uses one, enter it separately with its real hydration rather than lumping it into the main water, or the total will be off in whichever direction the preferment leans.
Enriched doughs carry hidden water
Milk, eggs, and even honey are mostly water, so brioche and enriched loaves run wetter than their plain water suggests. Butter and oil add little water but do soften the dough in other ways. Fold the add-in water in for a truer picture, and remember flour type matters too — whole grain and high-protein flours drink more, so use the number as a starting target you adjust by feel.