Baking guides

Baker's percentages explained, with a worked bread formula

Professional bakers write recipes as percentages of the flour weight. Once you can read and write a formula this way, you can scale it to any batch size, compare it with other recipes and spot an error at a glance. This guide works through one real formula from start to finish.

Last reviewed: 2026-10-25

Open the Baker's Percentage Calculator →

The one rule: flour is always 100%

In baker's percentage, every ingredient's weight is written as a percentage of the total flour weight. The flour itself is therefore always 100%, and every other ingredient is measured against it. King Arthur Baking's pro reference gives the calculation as: ingredient weight ÷ flour weight × 100. Its example: 33 lb of water with 50 lb of flour is (33 ÷ 50) × 100 = 66%.

Because the flour is the base and not the whole dough, the percentages add up to more than 100%. That is not an error; it is the point. If you change the water from 66% to 70%, nothing else in the formula has to be recalculated, because none of the other percentages depends on the water.

The reasons King Arthur gives for working this way are the ones every baker runs into: precision (one unit of measure, by weight), easy scaling, and a shared language. A baker who reads "70% water, 2% salt" knows what kind of dough it is without seeing the batch size.

A worked lean bread formula

Here is a simple lean bread made with two flours. Start from the weights you actually used:

1. Add up all the flours: 900 g + 100 g = 1,000 g. This total is 100%.
2. Divide each other ingredient by 1,000 g and multiply by 100: water 680 ÷ 1,000 = 68%, salt 20 ÷ 1,000 = 2%, yeast 10 ÷ 1,000 = 1%.
3. Each flour is also shown as its share of the flour total: 900 ÷ 1,000 = 90% bread flour, 100 ÷ 1,000 = 10% whole wheat.
4. Add all the percentages: 100 + 68 + 2 + 1 = 171%. This is the total (or formula) percentage. The dough weighs 1,710 g, which is 171% of the 1,000 g of flour.

The water percentage, 68%, is also the dough's hydration. The hydration guide explains what that number tells you and how to change it.

You can check any formula like this in the Baker's Percentage Calculator: enter the flour and ingredient weights and it shows each percentage, the total dough weight and the hydration.

Scaling to any dough weight

Say you need six 500 g pieces of dough, so 3,000 g in total. Divide the target dough weight by the total percentage written as a decimal, and you have the flour weight:

Flour = 3,000 g ÷ 1.71 = 1,754 g

Every other ingredient is then flour × its percentage: bread flour 1,754 × 0.90 = 1,579 g, whole wheat 1,754 × 0.10 = 175 g, water 1,754 × 0.68 = 1,193 g, salt 1,754 × 0.02 = 35 g and yeast 1,754 × 0.01 = 17.5 g. Together they come to 3,000 g (2,999.5 g before rounding). The percentages never changed; only the batch did.

King Arthur Baking calls the same step the formula conversion factor: desired dough weight ÷ sum of the percentages. Its French bread example adds up to 168.25% (100% flour, 65% water, 2% salt, 1.25% yeast). For 150 lb of dough the factor is 150 ÷ 168.25 = 0.8915, which they round up to 0.9 because a little extra dough is better than too little. That gives 90 lb flour, 58.5 lb water, 1.8 lb salt and 1.13 lb yeast, 151.43 lb in total.

In practice, allow a little extra for dough that stays in the bowl and on the bench, and remember that bread loses weight in the oven. If the finished loaf has to weigh 500 g, the dough has to weigh more: the Bake Loss Calculator works out how much.

Baker's percentage vs true percentage

Sometimes you need each ingredient's share of the whole dough instead, for example for a label or a nutrition calculation. That is the true percentage. Wikipedia's article on baker percentage gives the conversion: true % = baker's % ÷ total percentage × 100.

In the worked formula, water is 68 ÷ 171 × 100 = 39.8% of the dough, and flour is 100 ÷ 171 × 100 = 58.5%. True percentages add up to exactly 100%, which is why they are awkward for scaling: change one ingredient and every other share moves.

Two or more flours

All flours together make the 100%. That includes whole wheat, rye, spelt or semolina, and in an overall formula it includes the flour in a starter or preferment too (see below). A formula with 80% bread flour and 20% rye has 100% flour in total, and the water, salt and yeast are measured against that total, not against the bread flour alone.

Different flours absorb different amounts of water, so two doughs with the same percentages can feel quite different. Wikipedia notes that baker's percentages say nothing about the flour's protein, so formulas may need adjusting for a different country, miller or flour type.

Where preferments fit

A preferment (poolish, biga, levain or sourdough starter) is made from part of the dough's flour and water ahead of time. There are two ways to write it.

• As one ingredient: the preferment gets its own percentage of the flour in the final mix, like any other ingredient. King Arthur notes that a preferment is treated as one ingredient in the formula.
• As an overall formula: the preferment is broken into its flour, water and yeast, which are added to the rest of the dough's flour, water and yeast, and all the percentages are recalculated on the total flour. King Arthur calls this the overall baker's percent.

King Arthur's poolish example: the poolish is made with equal weights of flour and water plus 0.1% yeast, and it weighs 96% of the final dough's flour. Once its flour and water are added back in, the overall formula is 59.44 lb flour (100%), 38.64 lb water (65%), 1.19 lb salt (2%) and 0.74 lb yeast (1.25%).

The overall formula is the one to use when you compare doughs or talk about hydration; without it, a dough whose water is partly hidden in a starter looks drier than it is. The preferments guide works through the maths for poolish, biga and levain.

Typical ranges

Wikipedia gives a common basic bread formula as 100% flour, 60% liquid, 1% yeast, 2% salt and 1% fat (oil, lard or butter). It also cites a source saying the taste of yeast is generally not noticeable unless the yeast is above about 2.5% of the flour weight. Typical water percentages by dough type:

These ranges are a way to sanity-check a formula. If a recipe for sandwich rolls works out at 85% water, either it is unusual on purpose or a number was copied wrong.

Common mistakes

• Using the total dough weight as the base. The base is always the flour.
• Counting only the main flour. Every flour in the dough is part of the 100%.
• Ignoring the flour and water in a starter when quoting hydration.
• Converting from cups. Percentages only work with weights; weigh the ingredients first.
• Rounding yeast and salt too hard on small batches. On 500 g of flour, 1% yeast is 5 g, and 1 g either way is a 20% change.

Frequently asked questions

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