Baker's Percentages: A Guide to Bakers Math

You've probably heard a baker mention hydration, or seen a recipe written in percentages and wondered what it meant. Baker's percentages are the system behind both — a way of reading and building recipes based on ratios rather than fixed amounts.

Don't let the word "math" put you off. Baker's percentages involve simple division, and this guide will walk you through everything you need to know.

What Are Baker's Percentages?

Baker's percentage (also called baker's math) is a way of writing bread recipes where every ingredient is expressed as a percentage of the total flour weight, with flour always set at 100%.

Once the logic clicks, it changes how you read recipes. You can look at a formula and instantly understand what the dough will be like. You can scale a batch to any size without doing complex conversions. And eventually, you can start building your own recipes from scratch rather than following someone else's.

This means a recipe can be expressed two ways (in weights or in percentages) and both say exactly the same thing. Take this simple bread recipe: expressed as weights on the left, and as baker's percentages on the right.

One thing that trips people up: because flour is always 100% and every other ingredient is a percentage of that, the percentages in a recipe will always add up to more than 100%. This is normal and expected, it's not a percentage of the whole recipe, it's a percentage of the flour.

Why Use Baker's Percentages?

Baker's percentages serve two important functions:

They give you a quick snapshot of a recipe. At a glance, you can see the relationship between ingredients and understand what the dough will be like before you even mix it. A recipe at 80% hydration will be wetter and more extensible than one at 65%. A recipe with 2.5% salt is saltier than the standard 2%. Once you're familiar with typical ranges, you can evaluate a recipe just by reading the percentages.

They make scaling easy. Because everything is expressed relative to flour, you can scale a recipe up or down to any batch size while keeping the ratios exactly the same. You can also use percentages to create your own recipes from scratch, starting with the percentages you want and converting to weights.

Why you need a kitchen scale

To use baker's percentages, you need to work in weights, not volume. Ingredients vary in density, and a cup of flour doesn't weigh the same as a cup of water. A kitchen scale is essential — it makes baking more accurate and repeatable across the board.

How to Calculate Baker's Percentages

The formula is straightforward:

Weight of ingredient ÷ Weight of flour × 100 = Baker's percentage

Let's work through a simple example.

Using the formula above, here's how each ingredient calculates out:

What Hydration Means

You'll often hear bakers refer to the hydration of a loaf. Hydration is simply the water percentage in a recipe and it's the same calculation as above, just applied to the water.

A recipe with 1000g of flour and 750g of water is a 75% hydration dough. If a recipe calls for other liquids alongside water those also count toward the total hydration.

Hydration has a significant effect on the dough. Higher hydration doughs (above 75%) are wetter, stickier, and more extensible. They tend to produce a more open, irregular crumb but can be trickier to handle. Lower hydration doughs (65% and below) are stiffer and easier to shape, making them a good starting point for

If your dough is very sticky or difficult to handle, try reducing the water percentage by about 5% next time and adjust from there.

Converting Percentages to Weights

Once you understand baker's percentages, you can work in reverse: starting with percentages and converting to weights. This is useful for scaling a recipe to a specific batch size or creating your own recipe from scratch.

Step 1: Start with your baker's percentages and add them up.

Step 2: Decide on your desired total dough weight. Let's say you want to make three 800g loaves - you'll need 2,400g of dough.

Step 3: Find the conversion factor - this is the number that links your percentages to real weights. To find it, divide your desired dough weight by the total percentage:2,400 ÷ 173.5 = 13.8

This means your batch is 13.8 times larger than a batch where flour weighs exactly 100g. Multiply any percentage by 13.8 and you get the weight of that ingredient.

Step 4: Multiply each percentage by the conversion factor to get ingredient weights.

Now, you have a complete recipe scaled exactly to your batch size.

Soakers and Cooked Grains

For recipes that include soaked seeds or grains, the water used for soaking doesn't count toward the recipe's hydration. Most of it gets strained off before the seeds are added to the dough, so it doesn't meaningfully affect the final moisture level.

Cooked grains and porridge are different. When you add oat porridge or polenta directly to the dough, the water used in cooking stays in and becomes part of the dough's moisture, which means it does affect your overall hydration. If you're following a recipe, this is already accounted for. If you're building your own formula, it's worth keeping in mind.

Using Baker's Percentages to Evaluate a Recipe

Once you're comfortable reading baker's percentages, you can use them to quickly assess a recipe before you even start mixing. A few things to look for:

Salt typically falls around 2% in most bread recipes. Noticeably below that and the bread may taste flat; above 2.5% and it may start to inhibit fermentation.

Hydration gives you a sense of how the dough will handle. Higher hydration (75%+) is wetter and more extensible; lower (65% and below) is stiffer and easier to shape. See "A Note on Hydration" above for troubleshooting tips.

Starter percentage in a sourdough recipe tells you how quickly the dough will ferment and gives you a sense of the flavor profile. A higher starter percentage (30% or more) means faster fermentation and a generally milder loaf since there's less time for acid to develop. A lower starter percentage (10–15%) means a slower fermentation and a more complex, sour flavor. Most recipes fall somewhere in the 16–20% range, though there's plenty of room to go higher or lower depending on your timing and taste preferences.

Baker's percentages take a little getting used to, but the more you use them, the more natural they become — and the less you'll find yourself tied to a recipe.

Frequently Asked Questions

What is the formula for baker's percentages?
Divide the weight of an ingredient by the weight of the flour, then multiply by 100. Flour itself is always 100%, since it's the ingredient every other percentage is measured against.

Why do baker's percentages add up to more than 100%?
Because every ingredient is a percentage of the flour weight, not a percentage of the total recipe. Since there's always at least as much non-flour weight as flour weight in a dough, the percentages sum to more than 100% — that's expected, not an error.

What is a good hydration percentage for beginners?
Somewhere between 65–70% hydration is a good starting point. It's forgiving to handle and shape. Doughs above 75% hydration get progressively wetter and stickier, which makes them harder to work with until you've built up some experience.

How do you calculate baker's percentages with a sourdough starter?
Treat the starter as its own ingredient and divide its weight by the flour weight, the same as any other ingredient. For a more precise hydration number, you can break the starter into its flour and water components (assuming 100% hydration starter, that's an even split) and add those amounts to your totals before calculating.

How do you calculate baker's percentages with more than one type of flour?
Add up the weight of all the flours first — that combined total represents 100%. Then divide each individual flour's weight by that total to find its own percentage.

How do you scale a recipe using baker's percentages?
Add up all your baker's percentages to get a total. Divide your desired total dough weight by that total percentage to get a conversion factor. Multiply each ingredient's percentage by the conversion factor to get its weight in the new batch size.