Baker's Percentages Explained: How to Read and Scale Any Recipe

If you've ever opened a professional bread recipe and seen numbers like "70% hydration" or "2% salt," you were looking at baker's percentages. The system seems odd at first because the numbers don't add up to 100. Once you understand the logic behind it, though, you'll find it's one of the most practical tools in baking.

The core rule is simple: flour always equals 100%, and every other ingredient is expressed as a percentage of the total flour weight. That's the whole system. Everything else is just applying that rule.

Why Bakers Think in Percentages

Recipes written in grams or cups have a fixed yield. If you want to make two loaves instead of one, you have to double every number. That's easy enough. But what happens when you want to hit a specific dough weight, or you're scaling a recipe to fit the capacity of your mixer, or you're adjusting hydration to suit a wetter flour?

Regular recipe math gets messy fast. Baker's math solves this by anchoring every ingredient to the flour, which is the structural backbone of bread. Change the flour weight and all the other quantities move with it in proportion.

A recipe written in percentages is also much easier to compare and analyze. You can look at two sourdough recipes side by side and immediately see that one is a 75% hydration dough and the other is 80%, without having to do any mental division. You can spot that one uses twice as much salt as the other. That kind of at-a-glance reading is genuinely useful once you start baking regularly.

How to Calculate Baker's Percentage

The formula for any ingredient is:

Ingredient % = (Ingredient weight ÷ Total flour weight) × 100

So if a recipe calls for 500g of flour and 350g of water:

350 ÷ 500 × 100 = 70%

The water is at 70% of the flour weight. You'd also say this dough has 70% hydration. For a deeper look at why hydration matters to the final texture of your loaf, see what dough hydration is and why it matters.

To go the other direction (from percentage to grams), you rearrange:

Ingredient weight = (Ingredient % ÷ 100) × Flour weight

So if you want to know how much water you need at 70% hydration for 750g of flour:

(70 ÷ 100) × 750 = 525g

A Real Formula in Baker's Percentages

Here's a basic white sandwich loaf written out in full.

Ingredient	Weight (g)	Baker's %
Bread flour	500	100%
Water	350	70%
Salt	10	2%
Instant yeast	5	1%
Butter (softened)	25	5%
Total dough weight	890g	—

The total dough weight (890g) is just the sum of all ingredient weights. It's not the same as the sum of the percentages (178%), which is a number only useful for one thing: scaling.

Scaling the Recipe Up or Down

Suppose you want to make a larger loaf and you need 1,200g of finished dough. Here's how to find the new flour weight and recalculate every ingredient.

Step 1: Divide the target dough weight by the sum of all percentages (expressed as a decimal).

The sum of percentages is 100 + 70 + 2 + 1 + 5 = 178%, or 1.78 as a decimal.

1,200 ÷ 1.78 = 674g flour (rounded to the nearest gram)

Step 2: Apply each percentage to that new flour weight.

Ingredient	Baker's %	New Weight (g)
Bread flour	100%	674
Water	70%	472
Salt	2%	13.5
Instant yeast	1%	6.7
Butter	5%	33.7
Total	—	~1,200g

Round salt and yeast to the nearest half-gram. Your kitchen scale probably has 1g resolution anyway, so 14g of salt and 7g of yeast is perfectly workable.

This same math works if you want to scale down to a small test loaf. Say you only want 400g of dough to try a new recipe before committing to a full batch:

400 ÷ 1.78 = 225g flour

Then multiply each percentage by 225 to get the rest. Fast, clean, no guesswork.

How to Convert an Existing Recipe to Percentages

You already have a recipe you love, and you want to express it in baker's percentages so you can scale it freely. Here's the process.

First, make sure every ingredient is in the same unit, grams being the most precise. If your recipe gives volumes (cups, tablespoons), weigh the ingredients instead. Volume measures are inconsistent enough to cause real problems once you start scaling.

Then pick out the total flour weight. In most recipes that's obvious. In enriched doughs, everything that's called "flour" counts (bread flour plus whole wheat, for instance, adds together). Starter or poolish is trickier: the flour and water inside a pre-ferment each count toward their respective totals. More on that below.

Once you have the flour weight, divide each ingredient by it and multiply by 100. Write those numbers down. You now have a portable recipe you can scale to any batch size without touching the proportions.

Dealing with Pre-ferments and Sourdough Starter

Sourdough starter and poolish both contain flour and water, which means you need to account for them when calculating percentages. This is called the "total formula" approach.

If your recipe includes 200g of active starter at 100% hydration (equal parts flour and water by weight), that starter contains 100g of flour and 100g of water. Those amounts add into your total flour and total water columns before you calculate percentages.

So a recipe with 400g of bread flour plus 200g of starter (100g flour, 100g water) has a total flour weight of 500g. The water in the starter counts toward hydration. This is why two sourdough recipes that look different on the surface can end up at the same hydration percentage once you do the math.

Understanding how that hydration changes the feel of the dough during mixing is important for knowing what to expect. A wetter dough takes longer to develop gluten, which connects to what you feel when kneading bread dough by hand and checking it's ready.

Using a Baker's Percentage Calculator

You don't have to do this math by hand every time. A basic spreadsheet does the job perfectly. Set up one column for ingredient names, one for weights, and one formula that divides each weight by the flour weight cell. Change the flour weight and everything recalculates automatically.

There are also dedicated baker's percentage calculator tools online. They're useful for quick checks or when you don't have a spreadsheet handy. The math they're doing is exactly what's described here, so once you understand the system, using a calculator is just a shortcut rather than a mystery.

The bigger skill is reading a recipe written in percentages and knowing what those numbers mean for how the dough will behave. High hydration (above 75%) means a slack, sticky dough that's harder to shape. A 2% salt recipe is standard; 2.5% will taste noticeably saltier. Enriched doughs with fat and sugar percentages above 20-30% need more yeast or more time to rise because the enrichment slows fermentation.

What the Numbers Tell You

Once you're comfortable with baker's math, you start reading recipes differently. A 65% hydration dough with 1% yeast is easy to handle and rises predictably. A 90% hydration ciabatta is nearly pourable and requires a very different technique. You know this before you mix a gram.

For gluten-heavy doughs, the percentage of protein-rich flour also tells you how much structure is available. High-hydration whole grain doughs behave differently from high-hydration white doughs partly because whole grain absorbs more water. Bakers express this by adjusting the water percentage rather than guessing how wet to make things.

All of this connects to understanding how the gluten network actually forms and what a well-developed dough looks and feels like. The windowpane test for checking gluten development is one reliable way to see whether the dough is ready, regardless of what the percentages say the hydration is.

Frequently Asked Questions

Why don't baker's percentages add up to 100?

Because the flour is used as the base reference (100%), not the total batch. Every other ingredient is a percentage of the flour, so the numbers can easily sum above 100%. A 70% hydration dough with 2% salt and 1% yeast totals 173%, which just reflects the ratio structure, not a percentage of a whole.

Do I need to use baker's percentages for everyday home baking?

No, and plenty of experienced home bakers never use them. But if you bake regularly, adjust recipes, or want to understand why a dough behaves a certain way, they're worth learning. The main payoff is scaling: it's much easier to hit a specific dough weight when you can do the math directly instead of proportionally adjusting each ingredient by trial and error.

How do I handle recipes that list ingredients in volume measures?

Convert to grams before doing anything else. Flour in particular varies widely by volume depending on how it was measured. A cup of sifted flour and a cup of packed flour can differ by 30g or more. Weigh everything with a kitchen scale and you sidestep the problem entirely.

What's a typical hydration percentage for a beginner loaf?

Somewhere between 65% and 72% is a comfortable range for most beginning bakers. The dough is workable, holds its shape reasonably well, and isn't so slack that shaping becomes frustrating. As your technique develops, you can push higher if you want a more open crumb.

Can I use baker's percentages for non-bread baking?

Technically yes, though the conventions differ. Pastry chefs sometimes use a similar ratio-based system for things like pie dough or cookie formulas, but flour isn't always the base (fat might be). Baker's percentages specifically refer to the bread-baking convention where flour anchors everything. For bread and yeasted doughs, it's the standard professional approach.