Guide 01 · Start here

Baker’s percentages without the headache

Baker’s math might look complicated, but the basic idea is wonderfully simple—and once you see it, recipes become much easier to understand.

6 minute read

Why is flour always 100%?

In ordinary percentages, the whole of something adds up to 100%. Baker’s percentages work differently. Flour is the reference point—the ingredient every other ingredient is compared with—so the total flour weight is always labeled 100%.

If your dough contains 500 grams of flour and 350 grams of water, the water is 70% of the flour weight. Divide 350 by 500, then multiply by 100. That is a 70% hydration dough.

350g water÷500g flour× 100= 70%

A familiar sourdough formula

A straightforward loaf might use 500 grams of flour, 350 grams of water, 100 grams of ripe starter, and 10 grams of salt. Written in baker’s percentages, it becomes:

Ingredient	Weight	Baker’s %
Flour	500g	100%
Water	350g	70%
Starter	100g	20%
Salt	10g	2%

This is the language used by the calculator in My Proofing Box. Tell it how much dough you want, and it works backward from these ratios to give you the ingredient weights.

What if I use more than one flour?

All flour counts toward the 100%. A blend of 400 grams all-purpose flour, 75 grams whole wheat, and 25 grams rye contains 500 grams total flour. The blend is therefore 80% all-purpose, 15% whole wheat, and 5% rye.

That distinction is useful because “75% hydration” does not describe the entire personality of a dough. A mostly white dough and a whole-grain dough can have the same hydration on paper and feel quite different in your hands.

The starter question

Here is where bakers can sound as if they are arguing when they may simply be using two different conventions. Some recipes list starter as its own percentage, just as My Proofing Box does. Other formulas separate the flour and water inside the starter and include them in the dough’s total flour and total water.

Neither approach is morally superior! For everyday recipe building, listing a 100%-hydration starter as 20% is clear and practical. For comparing formulas with absolute precision, including the flour and water inside the starter gives you the dough’s true overall hydration. The important thing is knowing which convention a recipe uses.

Why bother with any of this?

Scale without rewriting the recipe. Make one loaf or four while keeping the dough consistent.
Compare recipes quickly. A glance tells you which dough is wetter, saltier, or more heavily inoculated.
Make useful changes. Increase hydration by 2% instead of adding an unrepeatable “splash.”
Keep better notes. Your next loaf can respond to your last one instead of beginning from scratch.