Baker's Percentage Calculator: Flour, Water, Salt and Yeast by Weight

1. Leave Start from on Flour weight and enter your flour in grams. Flour is always 100 percent.
2. Enter the hydration (water), salt and yeast percentages. Add sugar, fat or up to two custom ingredients if your recipe needs them.
3. Read each ingredient in grams and the total dough weight. To size a batch to a tin or basket instead, switch Start from to Total dough weight and the tool solves the flour for you.

What each result tells you:

The hydration, salt and yeast values loaded here are common starting points, not fixed rules. Change them to match your own recipe before you rely on the grams.

Baker's percentage (also called baker's math or formula percentage) is a way to write a bread recipe by weight, with flour fixed at 100 percent. Every other ingredient is listed as a percentage of the total flour weight, not of the whole dough.

So a recipe at 70 percent hydration means the water weighs 70 percent of the flour. At 2 percent salt, the salt weighs 2 percent of the flour. Because flour is the anchor, the same percentages describe a 500 g test loaf and a 50 kg bakery batch. You just change the flour weight.

It is the standard language of bread and pastry formulas because it makes a recipe easy to scale, compare and adjust. For sourdough specifically, our sourdough hydration calculator handles the flour and water hidden inside a starter.

The maths is pure ratio arithmetic. Flour is 100 percent, and each ingredient weight is simply the flour weight multiplied by that ingredient percentage.

1. Set the base. Flour is 100 percent by definition.
2. Scale each ingredient. Multiply flour by each percentage to get grams.
3. Add them up. The sum of flour and every ingredient is the total dough weight.
4. Or reverse it. Divide a target dough weight by the total formula percentage to find the flour, then scale as above.

No ingredient density, oven data or market figure is involved. The only inputs are your flour weight and the percentages you choose, so the arithmetic is exact to the precision you enter.

Take a simple lean bread: 1000 g flour at 70% hydration, 2% salt and 1% yeast, with no sugar or fat.

Meaning: the formula totals 173 percent of the flour, so 1000 g flour makes 1730 g of dough. To go the other way, a 1730 g dough target divided by 1.73 gives exactly 1000 g flour, and the ingredients scale from there. This is the worked example the calculator loads by default.

The most common confusion is reading a percentage against the dough instead of against the flour. Baker's percentage always divides by flour, which is why the percentages add up to more than 100.

On the example loaf the water is 70 percent in baker's terms (700 / 1000), but only about 40.5 percent of the finished dough (700 / 1730). Both are correct; they answer different questions. Bakers use the flour-based figure because it stays the same at any batch size.

When a recipe quotes a percentage, assume it is baker's percentage unless it clearly says otherwise. This calculator works entirely in baker's percentage.

Hydration

Water as a percentage of flour is the dial that most changes a dough. Stiffer doughs sit lower; open, rustic crumb needs more. Flour type matters too: strong bread and whole-grain flours drink more water than plain white flour, so the same percentage can feel different.

Salt

Salt is usually a narrow band because it is about taste and dough strength, not volume. Too little tastes flat; too much slows the yeast noticeably.

Yeast or Starter

The yeast percentage trades against time and temperature. A long, cool rise uses very little; a fast, warm proof uses more. A pre-ferment or sourdough starter carries its own flour and water, which shifts the real hydration.

Enrichment: Sugar and Fat

Sugar and fat turn a lean dough into an enriched one. They soften crumb and slow gluten development, so enriched doughs often need a little more yeast or time.

Custom Ingredients

Milk, eggs, seeds and cocoa all carry water or change texture. Enter them as their own percentage of flour so the whole formula scales together.

Scaling a Recipe Up or Down

Keep the percentages, change only the flour weight, and every ingredient scales in proportion. This is the fastest way to turn a one-loaf recipe into a four-loaf batch.

Sizing a Batch to a Tin or Basket

Switch to the reverse mode, enter the total dough weight your tin or banneton holds, and read the flour and ingredients that hit it exactly.

Comparing Two Recipes

Converting both to baker's percentage puts them on the same footing, so you can see at a glance which is wetter, saltier or more enriched.

Developing Your Own Formula

Start from a known percentage set, change one dial at a time, and record what works. Percentages make the change repeatable at any size.

1. Dividing by Total Dough

Percentages are of the flour, not the whole dough. Dividing by total weight gives numbers that look right but scale wrong.

2. Forgetting Starter Flour and Water

A sourdough starter is part flour and part water. Ignore that and your real hydration is higher than the recipe says.

3. Treating Defaults as Rules

The 70 / 2 / 1 starting point here is a convention, not a law. Your flour and method may want different numbers.

4. Measuring by Volume

Cups of flour vary a lot by scoop and settling. Baker's percentage only works reliably when you weigh ingredients on a scale.

5. Rounding Too Early

Round only the final grams, not the mid-step numbers, especially on small home batches where a gram or two of salt matters.

The arithmetic is exact. What it cannot do is predict how a specific dough will behave, because that depends on ingredients and technique the maths never sees.

Use the grams as a formula to weigh out, then adjust hydration and timing by feel. The numbers are a starting map, not the finished loaf.

It is a way to write a recipe by weight with flour fixed at 100 percent. Every other ingredient is given as a percentage of the total flour weight, so 70 percent water means the water weighs 70 percent of the flour.

Because they are all measured against the flour, not against the whole dough. Flour alone is 100 percent, so once you add water, salt and yeast the formula total naturally climbs above 100.

Multiply the flour weight by the hydration percentage divided by 100. For 1000 g flour at 70 percent hydration, water is 1000 x 0.70 = 700 g.

It depends on the bread and your flour. Lean breads commonly sit near 60 to 75 percent, while ciabatta and rustic loaves go higher. The default 70 percent is a common starting point you should adjust to your recipe.

Salt is often around 1.8 to 2.2 percent of the flour, and instant yeast is often near 0.5 to 2 percent depending on how fast you want the dough to rise. These are guidance ranges, not fixed rules.

Keep every percentage the same and change only the flour weight. Because each ingredient is a fixed share of the flour, the whole recipe scales in proportion to any batch size.

Yes. Switch Start from to total dough weight and enter the weight you need. The tool divides it by the total formula percentage to find the flour, then scales each ingredient.

Not directly. A starter carries its own flour and water, which raises your true hydration. Account for the starter separately, for example with our sourdough hydration calculator, then enter the adjusted percentages here.

Weigh them. Baker's percentage is a weight system, and cups of flour vary widely by how you scoop and settle them. A kitchen scale is what makes the formula reliable.

No. The calculation runs entirely in your browser and nothing is sent to our servers. Anything you choose to Save stays in this browser only.

• Sourdough hydration: flour and water inside a starter (MultiCalculators tool).
• Metric converter: convert between grams, kilograms and other units (MultiCalculators tool).
• King Arthur Baking: baker's percentage and ingredient weight guidance (standard formula convention, read 2026-10-06).