Baker’s Percentage, Explained

Baker’s percentage is the standard notation for bread formulas worldwide. Every professional bakery uses it. Every serious bread book writes formulas in it. Once you understand it, you can scale any recipe to any size, compare two formulas at a glance, and diagnose problems before the dough is mixed.

The one-sentence version

Flour weight is 100%. Every other ingredient is expressed as a percentage of that flour weight. That is the entire system.

Why this matters

Without baker’s percentage, recipes are locked to one batch size. Doubling “2.5 teaspoons yeast” introduces rounding errors that compound. Substituting one flour for another is guesswork. Comparing two recipes from different books requires recalculating everything from scratch.

With baker’s percentage, all three problems disappear. A recipe that reads “72% hydration, 2% salt, 20% starter” tells you exactly what the dough will feel like and how it will behave, regardless of whether you are making one loaf or twenty.

A concrete example

A basic sourdough recipe in weights: 500g bread flour, 375g water, 100g starter at 100% hydration, 10g salt. Convert each ingredient by dividing its weight by the flour weight and multiplying by 100:

Flour: 500/500 × 100 = 100%. Water: 375/500 × 100 = 75%. Starter: 100/500 × 100 = 20%. Salt: 10/500 × 100 = 2%.

Now the formula scales cleanly. Want to use 700g flour? Multiply: water = 700 × 0.75 = 525g, starter = 700 × 0.20 = 140g, salt = 700 × 0.02 = 14g. No rounding errors, no unit conversion. The baker’s percentage converter does this automatically in both directions.

The tricky part: starter contains flour and water

A 100% hydration starter is 50% flour and 50% water by weight. So 100g of starter is actually 50g flour + 50g water. The recipe above looks like 75% hydration at first glance, but the real calculation includes the starter’s contribution:

Total flour = 500g + 50g = 550g. Total water = 375g + 50g = 425g. True hydration = 425 / 550 × 100 = 77.3%.

That 2.3% gap is the difference between a comfortably shapeable dough and one that surprises you with slack. The hydration calculator accounts for this automatically.

Common baker’s percentages

Standard ranges in home sourdough baking:

Water (hydration): 65–80%. Lower for sandwich breads, higher for open-crumb artisan loaves. 72% is probably the most common home target.

Starter: 15–25%. Lower starter percentages give a longer, more flavorful fermentation. Higher percentages speed things up. 20% is the standard default.

Salt: 1.8–2.2%. Below 1.5% tastes flat. Above 2.5% suppresses fermentation. 2% is the near-universal standard (Hamelman, Reinhart, and Forkish all default to 2%).

Whole grain in a blend: 10–30%. Adds flavor and nutrition. Above 30%, handling changes noticeably. Sugar (enriched): 5–15%. Butter: 5–15%. Oil (focaccia): 5–10%.

How to convert any recipe

Three steps. First, identify the total flour weight (combine all flour types if the recipe uses a blend). Second, divide each other ingredient’s weight by the total flour weight and multiply by 100. Third, write down both the weight and the percentage. The weight version tells you how to make that specific batch. The percentage version gives you the formula forever.

Why commercial bakeries rely on this

At 200 loaves per day, ingredient errors are costly. Baker’s percentage lets a bakery scale precisely for any batch size, maintain consistency across shifts and employees, adjust for flour variations (a new shipment absorbs differently), and train new staff quickly. The system is universal — a baker from Tokyo and a baker from San Francisco communicate in the same notation.

When baker’s percentage gets tricky

Non-standard starter hydrations. A 50% hydration (stiff) starter is 67% flour and 33% water, not 50/50. A 125% hydration (liquid) starter is 44% flour, 56% water. The starter feeding calculator handles these splits.

Enriched doughs with many ingredients. Brioche with flour, water, eggs, butter, sugar, milk, salt, and starter has eight ingredients to track. Write the percentages down or they blur together.

Preferments. If a recipe uses a poolish, biga, or sponge, calculate the total formula as the sum of preferment ingredients plus main dough ingredients, then express percentages from that total.

The habit worth building

When you find a recipe you like, convert it to baker’s percentage immediately and save both forms. Weights tell you how to make that specific loaf today. Percentages give you the formula — and that is what is transferable, scalable, and comparable. The baker’s percentage converter makes the conversion instant in either direction.