Sourdough Calculator.

A sourdough calculator turns a recipe’s ratios into weights. Most sourdough formulas are written as percentages rather than fixed amounts, because percentages scale. A recipe that works for one small loaf also works for four loaves, as long as the ratios stay the same. Doing that by hand means several steps of multiplication and subtraction, and the starter makes it harder because it contains flour and water of its own. This simple sourdough calculator removes the mental math so you can concentrate on the dough.

1. Choose your unit: grams, kilograms, ounces or pounds.
2. Enter the total dough weight you want to end up with, before it is divided into loaves.
3. Set the hydration, for example 75%.
4. Set how much starter to use as a percentage of the total flour, commonly 10–20%.
5. Set the salt, usually about 2%.
6. Read the weigh-out list: flour to add, water to add, starter and salt.

Everything updates as you type. Switch to Advanced mode for several flours, a loaf count, baker’s percentage columns and a levain builder.

Hydration is the weight of water divided by the weight of flour, shown as a percentage. If a dough has 500 g of flour and 375 ml of water, its hydration is 75%. Hydration decides how the dough feels and how the crumb turns out. Around 65–70% is easy to handle, 75% is a popular choice for an open crumb, and 80% or more is wet and sticky and rewards practice and strong flour. Whole grain flours absorb more water, so they usually need a little extra. To check the hydration of a dough you have already mixed, use the sourdough hydration calculator.

With sourdough there is a catch: the starter adds water and flour to the dough. A good sourdough hydration calculator counts them, otherwise the dough ends up wetter than the number you planned. This calculator splits your starter into its flour and water using the starter hydration you enter, then subtracts those amounts from what you add. The finished dough lands exactly on the hydration you chose.

Baker’s math, also called baker’s percentages, describes every ingredient as a percentage of the total flour weight. Flour is always 100%. Water at 75% means 75 ml of water for every 100 g of flour. Salt at 2% means 2 g of salt for every 100 g of flour. This is the standard language of bread formulas, so it lets you compare recipes, scale them up or down, and change one thing at a time. The calculator uses baker’s percentages for its inputs, and Advanced mode shows the percentage of each ingredient next to its weight. Read more in the formulas section, or turn any ingredient list into percentages with the baker’s percentage calculator.

Two different ideas are both called a starter ratio, and it helps to keep them apart.

• The starter percentage in a recipe is how much starter goes into the dough compared with the total flour. Most loaves use 10–25%. A higher percentage ferments faster and tastes milder, and a lower one ferments more slowly and develops more flavor. Set this in the calculator above.
• The feeding ratio describes how you build or refresh the starter itself, written as old starter : flour : water. A 1:5:5 feed means one part old starter, five parts flour and five parts water, all by weight.

To work out feeding amounts, use the sourdough starter ratio calculator. Enter the total starter you need and how soon you want it ready, and it shows the old starter, flour and water to weigh out.

Lower feeding ratios such as 1:1:1 or 1:2:2 peak in a few hours and suit daily feeding in a warm kitchen. Higher ratios such as 1:5:5 or 1:10:10 give each bit of starter more food, so it peaks later and fits an overnight build. The times depend on temperature and on how strong your starter is, so treat them as a guide and watch the starter rather than the clock. For a sourdough bread ratio, a typical loaf uses 65–80% hydration, 10–20% starter and about 2% salt, all measured against the total flour.

This calculator does not time your stretch and folds, but your hydration affects them. A stiffer dough around 65–70% builds strength quickly and may need only a couple of sets. A wetter dough at 75% or more is slack at first, so many bakers give it three or four sets of stretch and folds, spaced about half an hour apart during the early part of bulk fermentation, using wet hands and a gentle touch. Use the calculator to decide your hydration, then adjust your folding to how the dough actually feels. Thehydration calculator page has a table of common starting points.

• Simple by default. Simple mode shows only what a home baker needs, and Advanced mode adds the rest.
• Starter-aware. The flour and water in your starter are counted, so the numbers match what is in the bowl.
• Any unit. Switch between grams, kilograms, ounces and pounds without rounding drift.
• Private. Everything runs in your browser and your recipes are never uploaded.
• Free. No sign-up, no limits and no ads in the way of the tool.