Sourdough calculator

Tell it how many loaves, how big and how wet. It gives you grams for the bowl, the true hydration and the levain to build the night before. The numbers start at our everyday country loaf: change any of them and the rest follow.

Your bake

How many you are baking.

985 g of dough bakes to about a 900 g loaf.

Water as a share of the flour in the bowl.

Levain as a share of the flour.

100% is equal weights of flour and water.

2% is the classic. 1.8% if you like it mild.

The part of the flour that is whole wheat or rye.

Reset to our everyday country loaf

In the bowl

IngredientGramsBaker's %
Bread flour46290%
Whole grain flour5110%
Water38575%
Ripe levain7715%
Salt102%
Total dough985

The night before: build the levain

IngredientGramsRatio
Ripe starter9.11
Flour455
Water232.5
True hydration
72.7%
Counting the flour and water inside the levain.
Prefermented flour
9.1%
How much of all the flour arrives already fermented.

How the numbers work

Bakers write recipes as percentages of the flour, which is always 100%. Everything else is a fraction of it: 75% hydration means 75 g of water for every 100 g of flour. That is why a formula scales so easily. Change the flour and everything else moves with it.

The calculator works backwards from the dough you want. It adds up the percentages (100 + 75 + 20 + 2 = 197%) and divides: 985 g of dough ÷ 1.97 is 500 g of flour. Then 75% of that is water, 20% is levain and 2% is salt.

Why your real hydration is higher

A 100% hydration levain is half flour and half water. In the country loaf, 100 g of levain brings 50 g of each, so the dough really holds 425 g of water for 550 g of flour: 77.3%, not 75%. Recipes on this site quote the simpler number, the one you weigh into the bowl. The calculator shows both.

Questions

What hydration should I start with?

Somewhere between 70% and 75% with ordinary bread flour. Go up two or three percent per bake for as long as you can still shape the dough without it sticking to everything. Whole grain flour drinks more water, so give it a little more when you use a lot of it.

How much levain should I use?

Usually between 10% and 30%. More levain means a faster bulk ferment; less gives you a slower, more forgiving one. 20% is a good middle in a kitchen of about 24 °C.

Why build the levain at 1:5:5?

One part ripe starter to five parts flour and five parts water is usually ripe by morning when you feed it in the evening. If yours is past its peak by then, feed it at 1:8:8 or use cooler water.

Does it work for yeasted dough?

Set the levain to 0% and it gives you flour, water and salt. Add instant yeast yourself: about 1% of the flour for a same-day dough, less for a long, cold rise.

Can I send someone my formula?

Yes. The address bar changes as you type, so copy it, or use the button under the results. Whoever opens it sees exactly your numbers.