Baker’s Percentage Explained: How to Scale Any Bread Formula

Ever cut a bread recipe in half and ended up with a dough that felt stiff and dry? The problem is rarely your hands. Professional bakers avoid it by writing every formula as a percentage of the flour.

The One Rule: Flour Is Always 100%

Baker’s percentage rests on a single rule. Flour weight is always 100%, and every other ingredient is measured against it. The formula is ingredient weight divided by flour weight, times 100.

King Arthur Baking shows this with a white bread made from 50 pounds of flour. The water weighs 33 pounds, so 33 divided by 50, times 100, gives 66%. Salt at 1 pound is 2%, and yeast at 0.6 pound is 1.2%.

The unit does not matter as long as every weight uses the same one. You can check your own numbers with our baker’s percentage calculator, which does the division for you. The diagram below applies the rule to a 1,000 g batch.

Why flour? It is the main ingredient in bread, so it makes a steady anchor. When that anchor stays at 100%, you can compare a baguette formula with a pan loaf formula at a glance.

Hydration Is the Water Percentage

Hydration is the percentage of liquid in a dough, based on flour weight. If you mix 700 g of water into 1,000 g of flour, the dough has 70% hydration. A higher number simply means more water for the same flour.

King Arthur Baking gives no typical range for hydration, salt, or yeast. So treat any number as a recipe choice, not a rule. Formulas also differ by baker.

Take ciabatta. King Arthur’s example uses 73% water, while the preset in our calculator uses 80%. Neither is wrong; they are different formulas for the same style of bread.

Sourdough adds a starter, which changes how much water the dough holds. For that, use our sourdough hydration calculator instead of the plain formula here.

Hydration only describes water and flour on paper. It cannot tell you how a dough will feel, because flours differ. Use any formula as a starting point, then adjust to your own dough.

Three Real Formulas Side by Side

The best way to feel the system is to compare real formulas. This table uses King Arthur Baking’s examples. Pay attention to the last column.

Every total is well above 100%. That is normal, because flour already takes the whole 100% and the other ingredients stack on top. King Arthur’s French bread makes this clear: 120 pounds of flour, 78 of water, 2.4 of salt, and 1.5 of yeast total 201.9 pounds, or 168.25%.

Read across a row to see a whole formula at a glance. Read down a column to compare one ingredient between breads. Water runs from 65% to 73% across these three, while salt stays close to 2%.

A Worked Example With 1,000 g of Flour

Say your formula is 70% water, 2% salt, and 1% yeast, and you want to use 1,000 g of flour. Each ingredient is the flour weight times its percentage written as a decimal.

1. Set the flour. The flour is 1,000 g, which is 100%.
2. Find the water. Multiply 1,000 by 0.70 to get 700 g.
3. Find the salt and yeast. Multiply 1,000 by 0.02 for 20 g of salt, then by 0.01 for 10 g of yeast.
4. Add it up. The dough weighs 1,000 + 700 + 20 + 10 = 1,730 g, which is 173%.

That 173% is the total of every percentage in the formula. Keep it handy, because you need it for the reverse method later. Notice how small the salt and yeast weights are next to the flour. That is why a scale that reads to the gram matters.

Scaling a Formula to Any Batch Size

To scale a formula, pick a new flour weight and multiply again. The percentages never change. With 500 g of flour, the same formula needs 350 g of water, 10 g of salt, and 5 g of yeast, for an 865 g dough.

To change only the hydration, change only that percentage. At 75% water, the 1,000 g flour batch needs 750 g of water. The salt and yeast stay at 20 g and 10 g.

Many pro formulas use pounds, like King Arthur’s 50 pound examples. Convert with our imperial to metric converter or the general metric converter. The percentages stay the same either way. This is why bakers keep formulas in percentages: one formula page can serve a small home batch or a much larger one.

Working Backward From a Target Dough Weight

Sometimes you know how much dough you need, not how much flour. Divide the target dough weight by the total percent, written as a decimal. The answer is your flour weight.

Our formula totals 173%, so a 1,000 g dough needs 1,000 divided by 1.73, which is 578.0 g of flour. Then multiply that flour by each percentage. Water is 404.6 g, salt is 11.6 g, and yeast is 5.8 g. Carry the extra decimals through the math, and round only at the end when you set the final weights on your scale.

This reverse method helps when a pan or mixing bowl sets the size of the dough. The steps stay the same for any target, from one small loaf to a full tray of dough.

Common Mistakes That Skew the Math

A few slips cause most of the trouble when people first use baker’s percentage. Here are the ones to watch for.

• Using cups instead of grams. Percentages compare weights, and cup measures vary from scoop to scoop. Convert first with our baking measurement conversions from cups to grams.
• Dividing by the total dough. Always divide by the flour weight. Using the whole dough gives numbers that no formula uses.
• Expecting a 100% total. The grand total is always higher, such as 173% in our example.
• Copying one baker’s numbers as a standard. King Arthur lists no typical range, so formulas will differ.
• Rounding too early. Salt and yeast are small, so a rounded gram shifts their percentage more than it shifts flour.

Avoid these five, and the math will hold up from the smallest test loaf to the biggest batch.

FAQs About Baker’s Percentage

Sources and Further Reading

This article is general education about recipe math. Flours and ovens vary, so adjust any formula to your own dough. Reviewed for accuracy by Prof. Dr. Khalil Mudassar, PhD. Last updated 2026-10-13.