Sourdough Calculator

Sourdough Baking Is Easier When the Ratios Are Clear

Sourdough recipes look intimidating because bakers often describe them in percentages instead of simple cups and spoons. But that is exactly what makes sourdough easier once you understand the system. Baker’s percentages let you scale a loaf up or down without breaking the balance between flour, water, salt, and starter. Instead of hunting for a different recipe every time you want a larger loaf or a wetter dough, you keep the same structure and just change the total dough weight or hydration target.

This calculator helps you do that quickly. Enter your target dough weight, desired hydration, starter percentage, salt percentage, and starter hydration. The result shows your total flour, total water, salt, total starter weight, and the fresh flour and fresh water to mix after accounting for what is already inside the starter.

That last part matters. Many beginners accidentally double-count the flour and water in their starter. The dough still forms, but the hydration is off and the loaf behaves differently than expected. A good sourdough calculator removes that friction so you can focus on fermentation, shaping, and baking instead of redoing baker’s-math algebra every time you bake.

How Sourdough Baker’s Percentages Work

In baker’s math, total flour is always 100%. Everything else is expressed relative to that flour weight.

• Hydration % = total water ÷ total flour
• Salt % = salt ÷ total flour
• Starter % = total starter weight ÷ total flour

If your dough is 75% hydration with 2% salt, and you want 1,000 g of total dough, the calculator first solves for the total flour needed. Once the flour basis is known, it calculates the target water, starter, and salt. Then it splits the starter into its flour and water components based on the starter hydration you entered.

For a 100% hydration starter, the starter contains equal parts flour and water by weight. For a stiffer starter such as 60%, more of the starter weight is flour than water. That changes how much fresh flour and fresh water you need to add to the bowl.

Worked Example

Say you want 1,000 g of dough at 75% hydration with 20% starter and 2% salt, using a 100% hydration starter. The calculator solves total flour first, then builds the rest of the formula from that flour basis.

• Total flour is the anchor of the recipe
• Total water is 75% of that flour
• Total starter is 20% of that flour
• Salt is 2% of that flour

Because the starter is 100% hydration, half of the starter weight is flour and half is water. The calculator subtracts those starter contributions from the total flour and total water targets so you know how much fresh flour and fresh water to mix. That gives you a realistic working formula rather than just a theoretical percentage set.

This approach also makes it easy to move from one loaf to two, or from a 900 g batard to a 1,600 g Dutch-oven loaf, without changing the style of the bread.

How Hydration Changes the Dough

Hydration has one of the biggest effects on dough feel and finished crumb. Lower hydration doughs, such as 65% to 70%, are easier to shape and usually hold structure better, which makes them friendly for beginners. Higher hydration doughs, such as 75% to 85%, can produce a more open crumb and shinier interior but are stickier, less forgiving, and more dependent on flour strength and handling skill.

There is no universal “best” hydration. Whole-wheat flour often needs more water than white bread flour. Cooler kitchens, longer fermentation, stronger flour, and different shaping styles can all change what feels ideal. A calculator does not replace handling experience, but it does let you change one variable at a time with consistency.

That is why a good sourdough workflow is often: keep the starter percentage and salt constant, then test hydration in small steps. Moving from 72% to 75% tells you something useful. Jumping from 68% to 85% usually just creates chaos.

Starter Percentage and Fermentation Speed

Starter percentage changes how quickly dough ferments. More starter generally means faster fermentation and a shorter bulk rise, while less starter slows the process. This is especially useful when adapting dough to room temperature. In a warm kitchen, a lower starter percentage can buy you control. In a cooler kitchen, a slightly higher percentage can keep the schedule practical.

Typical starter levels for naturally leavened bread often land around 10% to 25% of flour weight, though bakers go outside that range for specific timelines and flavor goals. More starter can reduce the fermentation window, but it also changes flavor development and dough strength. The sweet spot depends on your flour, temperature, and schedule.

This calculator helps with the arithmetic, but your final choice should still be driven by how your dough behaves in your own kitchen. Sourdough is math plus observation, not math instead of observation.

Salt Is Small but Important

Salt percentages usually look tiny, commonly around 1.8% to 2.2%, but salt strongly affects flavor, gluten behavior, and fermentation speed. Too little salt can make dough ferment too fast and taste flat. Too much can slow fermentation and push the loaf toward an aggressively salty profile. Because the salt amount is small, mis-measuring it has a bigger impact than many beginners expect.

That is another reason gram-based formulas outperform volume-based baking for sourdough. The difference between 9 g and 12 g of salt is easy to track on a scale and easy to lose with rough spoon measurements. Once the loaf size changes, the need for scale-friendly percentages becomes even more obvious.

If you are experimenting, change hydration or starter percentage first. Keep salt steady until you know exactly why you are adjusting it.

Common Beginner Mistakes

• Double-counting starter flour and water: this throws off hydration and total dough weight.
• Changing too many variables at once: when flour, hydration, and starter percentage all change together, troubleshooting gets hard.
• Ignoring flour type: whole-grain flours usually absorb water differently than white flour.
• Using volume measures for sourdough math: percentages work best with grams.
• Assuming hydration alone determines crumb: fermentation, shaping, and baking all matter too.

The best use of a sourdough calculator is to make your process repeatable. Once the numbers are consistent, your baking notes become far more useful.