Understanding Baker's Percentages: The Secret Language of Bread Recipes

Baker's percentages may look intimidating when you first encounter them in a bread recipe. Instead of simply telling you to use 500 g of flour, 350 g of water, and 10 g of salt, a recipe might say 100% flour, 70% hydration, and 2% salt.

For experienced bakers, this system makes recipes easier to understand, compare, scale, and modify. For beginners, however, it can seem like an unnecessary mathematical complication.

The good news is that baker's percentages are actually very simple.

Once you understand one basic rule—that flour is always 100%—you can calculate the percentage of every other ingredient in the recipe.

Whether you're making a simple sandwich loaf, sourdough bread, focaccia, baguettes, or artisan bread in a cast iron bread oven, understanding baker's percentages gives you much more control over your dough.

What Are Baker's Percentages?

Baker's percentages, also called baker's math, express every ingredient as a percentage of the total flour weight.

The flour is always assigned a value of 100%.

Every other ingredient is calculated in relation to the flour.

For example, imagine a simple bread recipe containing:

• 500 g flour

• 350 g water

• 10 g salt

• 100 g sourdough starter

Using baker's percentages, the recipe might look like:

• Flour: 100%

• Water: 70%

• Salt: 2%

• Sourdough starter: 20%

Notice that the percentages do not need to add up to 100%.

The flour alone is 100%, while all the other ingredients are percentages relative to the flour.

Why Is Flour Always 100%?

This is the key to understanding baker's percentages.

The total flour weight is used as the reference point.

If your recipe contains 500 g of flour, that 500 g represents 100%.

To calculate the percentage of another ingredient, divide its weight by the flour weight and multiply by 100.

For example:

350 g water ÷ 500 g flour × 100 = 70%

Therefore, the dough has 70% hydration.

The same calculation works for every other ingredient.

The Basic Baker's Percentage Formula

The formula is:

Ingredient weight ÷ flour weight × 100 = baker's percentage

Let's say you have:

500 g flour
350 g water
10 g salt

For the water:

350 ÷ 500 × 100 = 70%

For the salt:

10 ÷ 500 × 100 = 2%

So your recipe is:

100% flour
70% water
2% salt

That's all there is to it.

What Does Hydration Percentage Mean?

Hydration is one of the most useful baker's percentages to understand.

Hydration tells you how much water the dough contains relative to the flour.

For example:

• 60% hydration = 300 g water per 500 g flour

• 65% hydration = 325 g water per 500 g flour

• 70% hydration = 350 g water per 500 g flour

• 75% hydration = 375 g water per 500 g flour

• 80% hydration = 400 g water per 500 g flour

Generally, higher hydration produces a wetter and more extensible dough, which can help create an open crumb in artisan and sourdough bread.

However, more water does not automatically mean better bread.

The flour's protein content, quality, milling, fermentation, and your ability to handle the dough all influence how much water it can absorb.

A 70% Hydration Sourdough Example

Let's say you want to make a sourdough loaf using 500 g of flour at 70% hydration.

You calculate the water like this:

500 × 0.70 = 350 g

Your recipe therefore contains:

• 500 g flour

• 350 g water

If you add 10 g salt:

10 ÷ 500 × 100 = 2%

So the recipe is:

• Flour: 100%

• Water: 70%

• Salt: 2%

The numbers immediately tell an experienced baker what kind of dough to expect.

Common Baker's Percentages for Bread

While there is no single formula that works for every type of bread, many recipes fall within familiar ranges.

Flour

100% — always.

Water

Approximately 55–85%, depending on the type of bread and flour.

Salt

Usually around 1.5–2.5%.

Instant yeast

Often around 0.5–2%, although the amount can vary considerably depending on fermentation time.

Sourdough starter

Often around 10–30% of the flour weight when using a 100%-hydration starter, although recipes vary widely.

These numbers are guidelines rather than strict rules.

How to Scale a Bread Recipe

One of the biggest advantages of baker's percentages is how easily you can change the size of a recipe.

Suppose your recipe is:

• 500 g flour

• 350 g water

• 10 g salt

That's 70% hydration and 2% salt.

Now you want to make a larger batch using 750 g flour.

Simply calculate each ingredient from the new flour weight.

Water:

750 × 0.70 = 525 g

Salt:

750 × 0.02 = 15 g

Your new recipe becomes:

• 750 g flour

• 525 g water

• 15 g salt

The ratios haven't changed. You've simply increased the amount of dough.

How to Make a Smaller Loaf

The same principle works in reverse.

Suppose you want a smaller loaf using 400 g flour.

At 70% hydration:

400 × 0.70 = 280 g water

At 2% salt:

400 × 0.02 = 8 g salt

Your recipe becomes:

• 400 g flour

• 280 g water

• 8 g salt

This is particularly useful when experimenting with different loaf sizes for a cast iron bread oven.

Why Professional Bakers Use Baker's Percentages

Baker's percentages aren't just a mathematical curiosity.

They allow professional bakers to communicate recipes precisely.

Instead of saying:

"Use 750 g flour and 525 g water."

A baker can say:

"Make a dough at 70% hydration."

That immediately communicates the relationship between flour and water.

It also makes recipes easier to reproduce at different scales.

A bakery producing hundreds of loaves can use the same formula whether it needs 5 kg of dough or 500 kg.

Home bakers benefit from the same flexibility.

Understanding Dough Formula vs. Recipe

A recipe tells you the actual quantities you need to weigh.

A formula describes the relationships between those ingredients.

For example:

Recipe

500 g flour
350 g water
10 g salt

Formula

100% flour
70% water
2% salt

The formula is more flexible because it can be scaled to virtually any quantity.

What Happens When You Increase Hydration?

Increasing hydration generally makes dough softer and stickier.

For example, compare:

65% hydration

500 g flour
325 g water

with:

80% hydration

500 g flour
400 g water

The 80% hydration dough contains 75 g more water.

That difference can have a major effect on handling.

Higher hydration can contribute to a more open and airy crumb, but the dough may require stronger gluten development and more careful shaping.

What Happens When You Reduce Hydration?

Lower hydration produces a firmer dough.

This can make shaping easier and allow the dough to hold its structure more readily.

Lower-hydration doughs are often useful for breads where a tighter crumb is desirable.

The important lesson is that hydration should match the type of bread you're trying to make and the flour you're using.

What Is Baker's Percentage for Salt?

Salt is usually calculated as a percentage of flour weight.

A common range is around 1.5–2.5%.

For example, with 500 g flour:

1.5% salt = 7.5 g
2% salt = 10 g
2.5% salt = 12.5 g

Salt does much more than add flavor.

It also influences gluten development and fermentation. Increasing or decreasing the salt percentage can therefore change how your dough behaves.

What Is Baker's Percentage for Yeast?

Yeast quantities can vary substantially depending on the recipe.

A dough designed for a long fermentation may use considerably less yeast than a dough intended to rise quickly.

For example, 0.5% yeast in 500 g flour equals:

500 × 0.005 = 2.5 g yeast

Meanwhile, 1% yeast equals:

500 × 0.01 = 5 g yeast

This illustrates why you should never assume that a certain amount of yeast is appropriate simply because it worked in another bread recipe.

Sourdough Starter and Baker's Percentages

Sourdough is where baker's percentages can become slightly more complicated.

When a recipe says it contains 20% sourdough starter, you need to know the hydration of that starter to calculate the true amount of flour and water in the dough.

A common sourdough starter is maintained at 100% hydration.

That means it contains equal weights of flour and water.

For example:

100 g starter = 50 g flour + 50 g water

This distinction becomes important when calculating the actual hydration of a sourdough recipe.

Understanding "Total Flour" in Sourdough

Let's look at a more advanced example.

Suppose a sourdough recipe contains:

• 450 g flour

• 100 g starter at 100% hydration

• 300 g water

• 10 g salt

The starter contains approximately:

50 g flour
50 g water

Therefore, the total flour in the dough is:

450 + 50 = 500 g

And the total water is:

300 + 50 = 350 g

The true hydration is therefore:

350 ÷ 500 × 100 = 70%

This is called calculating the recipe using the total flour.

It gives you a more accurate picture of the dough than simply calculating 300 g water against 450 g flour.

Why Sourdough Recipes Can Be Confusing

A sourdough recipe might tell you to use 500 g flour, 350 g water, and 100 g starter.

But whether that means 500 g total flour or 500 g flour plus the flour contained in the starter depends on how the recipe was written.

This is one reason two recipes that appear to have the same hydration percentage can behave differently.

How to avoid confusion:
Look for recipes that clearly state whether the baker's percentages include the flour and water contained in the sourdough starter.

What Is Prefermented Flour?

When working with sourdough, you may also encounter the term "prefermented flour."

This refers to the percentage of the total flour that has been fermented as part of the sourdough starter or levain.

For example, if a recipe has 500 g total flour and 50 g of that flour comes from the starter:

50 ÷ 500 × 100 = 10%

The prefermented flour is therefore 10%.

This percentage can help describe how quickly a sourdough dough is likely to ferment.

Baker's Percentages Make Recipe Comparison Easier

Imagine two sourdough recipes:

Recipe A

500 g flour
350 g water
10 g salt

Recipe B

750 g flour
525 g water
15 g salt

At first glance, the recipes look different.

Using baker's percentages, however, we can see that both are:

100% flour
70% water
2% salt

They are essentially the same formula at different scales.

This makes comparing bread recipes much easier.

Don't Assume a Higher Hydration Is Better

Higher hydration has become closely associated with open, artisan sourdough crumb.

But hydration is only one piece of the puzzle.

A 65% hydration dough that is properly fermented and shaped can produce a much better loaf than an 80% hydration dough that is under-fermented or poorly handled.

Higher hydration also requires more skill.

A very wet dough can be difficult to shape and may spread rather than rise if the gluten network isn't strong enough.

Baker's Percentages and Gluten Development

Water isn't the only ingredient that affects dough structure.

Flour selection is equally important.

Two flours can absorb very different amounts of water even when used at the same hydration percentage.

For example, a strong bread flour may handle 75% hydration comfortably, while another flour may become extremely sticky at the same percentage.

This is why baker's percentages are a starting point rather than an absolute prediction of dough behavior.

How to Convert Any Bread Recipe to Baker's Percentages

You can convert almost any bread recipe in a few simple steps.

Step 1: Identify the flour weight

This becomes your 100%.

Step 2: Weigh every other ingredient

Use grams whenever possible.

Step 3: Divide each ingredient by the flour weight

For example:

350 g water ÷ 500 g flour = 0.70

Step 4: Multiply by 100

0.70 × 100 = 70%

Repeat the calculation for salt, yeast, sugar, oil, milk, and any other ingredients.

Why Weighing Ingredients Matters

Baker's percentages work best when ingredients are measured by weight.

Volume measurements such as cups and tablespoons can vary considerably.

A cup of flour can have different weights depending on how it was scooped, settled, or packed.

A digital kitchen scale eliminates much of this uncertainty.

For bread baking, weighing ingredients in grams is one of the simplest upgrades you can make.

A Practical Example: Basic Artisan Bread

Let's create a simple artisan bread formula.

We want:

• 500 g flour

• 350 g water

• 10 g salt

• 1 g instant yeast

The baker's percentages are:

• Flour: 100%

• Water: 70%

• Salt: 2%

• Yeast: 0.2%

Now suppose we want to double the recipe.

We don't need to recalculate the percentages.

We simply use:

• 1,000 g flour

• 700 g water

• 20 g salt

• 2 g yeast

The formula remains exactly the same.

A Practical Example: Sourdough Bread

Consider a basic sourdough formula:

• 450 g flour

• 100 g 100%-hydration starter

• 300 g water

• 10 g salt

As explained earlier, the starter contributes approximately 50 g flour and 50 g water.

Total flour:

450 + 50 = 500 g

Total water:

300 + 50 = 350 g

The overall formula is approximately:

• Flour: 100%

• Water: 70%

• Salt: 2%

• Starter: 20% based on the total flour

This gives us a much clearer understanding of the actual dough.

How Baker's Percentages Help You Experiment

Once you understand baker's percentages, you can start modifying recipes deliberately instead of guessing.

Want a slightly wetter dough?

Increase hydration from 70% to 72%.

Want less salt?

Reduce it from 2% to 1.8%.

Want to experiment with a longer fermentation?

You might reduce the yeast percentage.

Want to make a larger loaf?

Increase the flour while keeping the percentages unchanged.

This turns bread baking into a controlled experiment rather than a process of trial and error.

A Simple Baker's Percentage Cheat Sheet

For a typical artisan bread, you might encounter something like:

Flour: 100%

Water: 65–80%

Salt: 1.5–2.5%

Instant yeast: approximately 0.1–1.5%, depending heavily on fermentation time

Sourdough starter: commonly 10–30%, depending on the formula and starter strength

These are broad ranges, not universal rules.

Different breads require very different formulas.

Baker's Percentages Don't Tell You Everything

Even a perfectly written formula doesn't tell the whole story.

It doesn't automatically tell you:

• How strong the flour is

• How active the starter is

• How warm the dough is

• How long fermentation should take

• How the dough should be shaped

• How much gluten development is required

• How long the loaf should be proofed

• How it should be baked

This is why two bakers can follow the same formula and produce very different loaves.

Baker's percentages describe the ingredients. The baker still has to understand the dough.

Using Baker's Percentages for Your Cast Iron Bread Oven

Baker's percentages are particularly useful when experimenting with artisan bread and sourdough in a cast iron bread oven.

Once you have a formula that works well for your flour and baking setup, you can easily scale it to fit the size of your bread oven.

For example, if a 500 g flour formula produces a loaf that fits your cast iron bread oven perfectly, you can keep that formula as your baseline.

If you want a slightly larger or smaller loaf, simply adjust the flour weight and calculate the remaining ingredients from the same percentages.

This makes it much easier to develop your own bread recipes.

Final Thoughts

Baker's percentages can seem complicated when you first encounter them, but the underlying idea is remarkably simple.

Flour is always 100%. Everything else is calculated in relation to the flour.

Once you understand that principle, you can:

• Scale recipes up or down

• Compare different bread formulas

• Understand hydration

• Adjust salt and yeast

• Calculate sourdough formulas

• Experiment with different doughs

• Develop your own bread recipes

More importantly, baker's percentages give you a common language for understanding bread.

Instead of simply thinking, "This recipe uses 350 g of water," you can think, "This is a 70% hydration dough."

That small change in perspective can make a big difference in your baking.

Whether you're making a simple loaf, experimenting with high-hydration sourdough, or baking artisan bread in a preheated cast iron bread oven, baker's percentages give you the tools to understand what you're making—and, eventually, to make it your own.