How to Convert Any Sourdough Recipe to Baker's Percentages
Once a recipe is in baker's percentages you can scale it to any size, compare it with other recipes and change one thing at a time. Here's the method, with a worked example.
Step 1: Get every ingredient in weight
Use grams or ounces, either works. If the recipe uses cups, weigh your own cup of flour the way you'd normally fill it, or use the weight the recipe author gives. Cup weights vary too much for a generic conversion to be reliable. Salt also varies by type: fine table salt is roughly 6 g per US teaspoon, while flaky or kosher salts are much lighter by volume. See the grams to ounces chart for unit conversions.
Step 2: Add up the flour
All the flour in the recipe together counts as 100%. Example recipe:
| Ingredient | Weight | Baker's % |
|---|---|---|
| Bread flour | 400 g | 80% |
| Whole wheat flour | 100 g | 20% |
| Water | 375 g | 75% |
| Starter (100% hydration) | 100 g | 20% |
| Salt | 10 g | 2% |
| Total | 985 g | 197% |
Step 3: Divide each ingredient by the flour
baker's % = ingredient weight ÷ total flour × 100. Water: 375 ÷ 500 × 100 = 75%. Salt: 10 ÷ 500 × 100 = 2%. The percentages add up to more than 100%. That's expected, because flour alone is 100%.
Step 4: Check the true hydration
The starter adds 50 g flour and 50 g water, so the true hydration is (375 + 50) ÷ (500 + 50) = 425 ÷ 550 = 77.3%, a little higher than the headline 75%. Whether that matters depends on the recipe, but it's worth knowing when you compare recipes. The starter percentage guide explains the different conventions.
Step 5: Scale to the size you want
Pick a total dough weight, then:
flour = total dough weight ÷ (sum of percentages ÷ 100)
For two 800 g loaves (1600 g total): 1600 ÷ 1.97 = 812.2 g flour. Then multiply out:
| Ingredient | Baker's % | For 1600 g |
|---|---|---|
| Bread flour | 80% | 649.7 g |
| Whole wheat flour | 20% | 162.4 g |
| Water | 75% | 609.1 g |
| Starter | 20% | 162.4 g |
| Salt | 2% | 16.2 g |
| Total | 197% | 1599.8 g (rounding) |
Round to whole grams for the bowl: 650 g, 162 g, 609 g, 162 g, 16 g.
Do it with the calculator
In the calculator enter total dough 1600, loaves 2, water 75%, starter 20%, starter hydration 100%, salt 2%. It shows 812 g flour (406 g per loaf), and you split the flour 80/20 yourself. It also reports the true hydration (77.3%).
Common gotchas
- Extra water added later (for example, held back and added during folds) still counts towards hydration.
- Milk, oil, honey and eggs are usually listed as separate percentages. Milk is roughly 87% water, which is worth remembering if you swap it for water.
- Inclusions such as seeds, nuts or cheese are also percentages of flour. Soaked seeds bring extra water with them.
- Whole grain swaps usually need more water; see whole wheat hydration. Changing between bread and all-purpose flour is covered in bread flour vs all-purpose.
Skip the arithmetic: enter your percentages and target dough weight and the calculator scales the recipe for any number of loaves.
Open the free calculatorFAQ
How do I calculate baker's percentage?
Divide each ingredient's weight by the total flour weight and multiply by 100. Flour is always 100%.
Why do baker's percentages add up to more than 100%?
Because flour alone is 100% and every other ingredient is expressed relative to it. A basic sourdough is often around 190–200% in total.
How do I scale a recipe to a different loaf size?
Add up all the percentages, divide your target dough weight by that total (as a decimal) to get the flour weight, then multiply the flour by each ingredient's percentage.
Can I convert a cup-based recipe?
Yes, but weigh your own cup of flour as you normally fill it, because cup weights vary widely. Once everything is in grams or ounces the maths is the same.