Baker's Percentages Explained, With Sourdough Examples

The one rule

In baker's percentages, the total weight of flour is 100%. Every other ingredient is expressed as its weight divided by the flour weight, times 100.

Ingredient % = ingredient weight ÷ flour weight × 100

So a dough with 1,000 g flour, 750 g water, 20 g salt and 10 g yeast is:

That is the example King Arthur Baking uses in its hydration guide, where 750 ÷ 1,000 gives 75% hydration.

Why bakers use it

Scaling. To make a batch with 650 g flour, multiply: 650 × 0.75 = 487.5 g water, 650 × 0.02 = 13 g salt. No ratios to juggle.

Comparing. Two recipes with different batch sizes are hard to compare in grams but easy in percentages. You can see at a glance that one is wetter or saltier than the other.

Adjusting. Want a slightly wetter dough? Change hydration from 72% to 75% and recalculate. The other ratios stay intact.

Diagnosing. If a loaf tastes flat, check salt %. If the dough is unmanageable, check hydration against similar breads.

Converting a recipe to percentages

1. Add up all the flours. That total is 100%.
2. Divide each other ingredient by the flour total and multiply by 100.
3. Write down the percentages next to the recipe.

Example: 450 g bread flour, 50 g rye, 360 g water, 10 g salt. Flour total 500 g. Bread flour 90%, rye 10%, water 72%, salt 2%.

Converting percentages to grams

1. Pick the flour weight, or work it out from the dough weight you want: flour = dough weight ÷ (sum of all percentages ÷ 100).
2. Multiply the flour weight by each percentage.

For two 900 g loaves at 100% flour, 75% water and 2% salt (177% in total): 1,800 ÷ 1.77 = 1,017 g flour, 763 g water, 20 g salt. Our baker's percentage calculator does this, including the starter.

Where sourdough starter fits

Starter is part flour, part water. There are two common ways to handle it:

• Total flour method: count the starter's flour as part of the 100% and its water as part of the hydration. This gives the true hydration of the dough, which is the approach King Arthur Baking's hydration guide takes. Our calculators use it.
• Starter as an ingredient: list starter as a percentage of the flour you add, like any other ingredient. Many recipes are written this way. It's fine for scaling, but the listed water percentage isn't the dough's real hydration.

When you adapt a recipe, check which method it uses. Our hydration calculator works out true hydration from any recipe's grams.

Common percentages

Ranges vary widely by bread, so treat these as reference points from the sources on this page rather than rules:

• Salt: 1.8–2% of flour in professional bread references.
• Hydration: around 60% is considered low or stiff; above about 80% is high hydration.
• Whole grain: often expressed as a share of total flour, such as 20% whole wheat.

What you need

A digital kitchen scale that reads in grams is the one essential tool. Weigh salt on a scale with 0.1 g resolution if you have one, since 1 g of salt is half a percent in a 200 g batch of flour.

Common questions

Why do baker's percentages add up to more than 100?

Because each ingredient is compared with the flour, not with the total dough. Flour 100% + water 75% + salt 2% = 177% of the flour weight.

What if a recipe uses two kinds of flour?

Add them together for the 100%. 400 g bread flour and 100 g whole wheat is 500 g flour: 80% bread flour and 20% whole wheat.

Can I use baker's percentages with cups?

Not reliably. Percentages are by weight, and a cup of flour can weigh quite different amounts depending on how it's filled. Use a scale.

Do I round the grams?

For home batches, rounding water and flour to the nearest gram is fine. Weigh salt as precisely as your scale allows, since small errors are a bigger share of a small amount.