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the hydration calculator

Two calculators in one notebook page. One for your starter, one for your dough — because they're different things, and most people learn that the hard way.

What this is & why it matters

Hydration is just a fancy word for "how much water is in this thing, relative to flour?" Bakers use it because it travels: a 75% hydration loaf in your kitchen behaves the same as a 75% hydration loaf in mine, even though our loaves are different sizes.

Two places this number shows up in sourdough — your starter (the jar of bubbly flour-water goo) and your dough (the actual bread). They get measured separately because they do different jobs. Pick a tab below for the one you need.

✎ A note: nobody nails this on the first try. Or the fifth. Hydration is the variable bakers spend years learning to feel in their hands. The math is just the starting point — your kitchen, your flour, your hands all weigh in too. (Unless you're my mom, in which case it'll be almost perfect on the first try, and she'll act surprised.)

your starter, decoded

A starter (or "levain" if you're feeling French) is just flour and water that's been encouraged to host wild yeast and bacteria. Its hydration is the ratio of water to flour, by weight. Most American recipes assume a 100% hydration starter — equal weights of flour and water — which has the consistency of thick pancake batter. Stiffer starters (50–65%) are common in Italy and behave differently: slower, milder, longer-lasting between feeds.

when you do a feed, how many grams of flour go in?
grams
how many grams of water at the same feed?
grams
Starter hydration
100%
Flour 50 g
Water 50 g
Total starter weight 100 g
Standard liquid starter You've got the all-purpose American sourdough starter. Fast, predictable, peaks in 4–6 hours at room temp. What 90% of online recipes assume.
advancedI want a specific hydration — work backwards

Trying to dial your starter to a specific hydration on purpose? Tell us how much flour you've got and what hydration you're shooting for, and we'll calculate the water.

grams
%
Add this much water
65
Flour 100 g
Water 65 g
Final starter weight 165 g

things worth trying

  • Stiffer is sweeter. Drop your starter to ~65% for a few weeks. The yeast outpaces the bacteria, and your bread will taste milder, more wheat-forward, less tangy.
  • Wetter is faster. Bump to 110–125% (especially with rye) and the starter will peak in half the time. Useful when you forgot to feed it.
  • Match your feed schedule to hydration. A 100% starter wants feeding every 8–12 hours at room temp. A 60% starter will hold for 24+ hours. Pick what fits your life.
  • Don't switch hydration mid-recipe. Recipes are written for a specific starter consistency. If yours is different, the dough hydration changes too. (Use Tab 02 to recalculate.)
if your first starter is too wet, too dry,
or just confusing — you're doing it right.
— xo, the kitchen

your dough, by the numbers

Dough hydration is the ratio of all the water in your dough to all the flour, by weight. The catch most beginners miss: your starter contains both flour and water, and they count too. A 100g blob of 100% starter is really 50g flour + 50g water in disguise. This calculator does the bookkeeping for you. Higher hydration → wetter dough, more open crumb, harder to shape. Lower hydration → tighter crumb, easier handling, denser bread.

the flour in the recipe (not counting starter)
grams
water you pour into the bowl (not the starter's water)
grams
total weight of the starter you add
grams
use Tab 01 if you don't know — defaults to 100%
%
most loaves are 1.8–2.2% — about 10g per 500g flour
grams
Total dough hydration
78%
Total flour (incl. starter) 550 g
Total water (incl. starter) 400 g
Starter contribution +50 g flour, +50 g water
Salt % 1.82%
Levain % 18.2%
Total dough weight 960 g
Sweet spot — open crumb territory 76–80% is where most modern country loaves live. Wet enough for big airy holes, dry enough to handle if you've practiced your stretches and folds.
advancedmulti-flour blends, baker's percentages, scaling

Real recipes mix flours — some bread flour, some whole wheat, a touch of rye. Add as many flours as you want. We'll calculate the blended hydration and show baker's percentages for everything (every ingredient as a % of total flour weight, the language professional recipes are written in).

flour name grams

baker's percentages

things worth trying

  • Start at 70%. If you're new, your first loaves should sit at 68–72% hydration. The dough is forgiving, shapeable, and the loaf will still have nice open crumb. Push higher only after you've baked a few good ones.
  • Whole grains drink more. If you swap bread flour for whole wheat or rye, add 3–5% more water. Whole grains absorb more — without that adjustment, your dough will feel weirdly stiff.
  • Salt is non-negotiable. 1.8–2.2% of flour weight. Less and your bread tastes flat; more and the yeast sulks. The recipe knows.
  • The starter hides water. 20% levain at 100% hydration adds 10% to your dough's water count. Forget this and your "75%" loaf is actually 82% — and you'll wonder why it's a puddle.
  • Pay attention to the dough, not the recipe. Same hydration feels different on different days. Cold flour, dry winter air, a different brand — all of it matters. The math gets you to the parking lot. Your hands park the car.
a flat first loaf is not a failed loaf.
it's the loaf that taught you something.
— save the math, log the bake, try again Sunday