The baker’s common language · Free calculator

Baker’s Math Calculator

Baker’s math expresses every ingredient as a percentage of total flour, which is why a formula written in percentages scales to any batch size. This calculator works the relationship in all three directions: give it any two of flour weight, ingredient weight, and baker’s percentage, and choose which third value Sourjoe should solve.

It’s the quickest way to answer questions like "how much salt is 2% of 850 g of flour?" or "if I used 720 g of water on 900 g of flour, what hydration is that?"

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? Baker's Math Calculator

? Enter any two baker's-math values and choose which third value Sourjoe should calculate.

? Calculate this field:

? Recipe Flour Amount

? Ingredient Amount

? Baker's Percentage

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Baker's Math

Why Bakers Use Percentages

A cup of flour can weigh anywhere from 120 g to 160 g depending on how it is scooped, so volume recipes drift. Baker's math fixes this by weighing everything and expressing each ingredient relative to the total flour, which is always set to 100%. Two things fall out of that one convention: any recipe can be scaled to any size with simple multiplication, and any two recipes can be compared at a glance — a 75% hydration dough is wetter than a 65% one no matter how many loaves either makes.

Reading a Formula

A sourdough formula written in baker's math looks like this — every line is a percentage of the 500 g flour:

Flour 500 g 100% Water 375 g 75% (375 ÷ 500 × 100) Levain 100 g 20% Salt 10 g 2%

Scaling a Recipe — the Three Questions This Calculator Answers

Each option in Calculate this field is one of the three everyday baker's-math questions:

What percent is this?
You used 375 g water with 500 g flour and want the hydration: 375 ÷ 500 × 100 = 75%. (Calculate: Baker's Percentage)

How much do I add?
You are mixing 800 g of flour and want 2% salt: 800 × 2 ÷ 100 = 16 g. (Calculate: Ingredient Amount)

How much flour fits my target?
You have 240 g of levain and your formula calls for 20%: 240 ÷ 0.20 = 1200 g flour. (Calculate: Recipe Flour Amount)

Common Baker's Percentage Ranges

Water:
60–85% typical bread range. Higher hydration usually means a looser dough and more open crumb potential.

Salt:
1.8–2.2% common lean-bread range. Salt affects flavour, gluten strength, and fermentation speed.

Leaven:
10–30% often used, depending on schedule, starter strength, and desired acidity.

Oil / Fat:
0–10% depending on style. Fat tenderizes crumb and can soften crust.

Sugar / Honey:
0–10%+ depending on enrichment. Sweeteners feed browning and tenderness.

Seeds / Inclusions:
5–30%+ depending on style. Soakers may be needed so inclusions do not rob water from the dough.

The Levain Subtlety (Worth Knowing)

A levain is itself flour + water, so a formula's stated hydration slightly understates the dough's true hydration. Example: 500 g flour, 375 g water, plus 100 g of a 100%-hydration levain (50 g flour + 50 g water) gives a true hydration of (375+50) ÷ (500+50) = 77%, not 75%. Casual baking can ignore this; formula development should not. Total flour also means all flours combined — in a 400 g bread flour + 100 g rye dough, rye is 20% and the flour basis is still 500 g.

Developer Notes / Model Logic

percent = ingredientG ÷ flourG × 100 ingredientG = flourG × percent ÷ 100 flourG = ingredientG ÷ (percent ÷ 100) grams = ounces × 28.349523125 ounces = grams ÷ 28.349523125

Worked example

Formula math in both directions: with 500 g of flour, a 2% salt target means 500 × 0.02 = 10 g of salt — that's solving for weight. Going the other way, if a recipe uses 380 g of water on that flour, 380 ÷ 500 = 76% hydration — solving for percentage. Give the calculator any two of the three values and pick which one Sourjoe should solve.

Where it fits in the bake

Baker's percentages are the shared language of every stage in the Baker's Process — the reason a formula scales from one loaf to five without breaking. When the ingredient you're solving for is water, graduate to the Hydration Calculator, which also counts the water hiding in your leaven.

Baker's Math Calculator FAQ

What is baker’s percentage?

A convention where total flour is always 100% and every other ingredient is expressed against it — 76% water, 2% salt, 20% leaven. It lets any two bakers compare recipes instantly and scale any formula to any batch size with one multiplication.

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

Because everything is measured against the flour, not the total dough. A classic 100% flour + 76% water + 2% salt + 20% leaven formula totals 198% — and that's correct. The total is a fingerprint of the recipe, not an error.

Does the flour in my starter count toward the 100%?

For quick formula work, most recipes treat the leaven as its own line item, which is what this calculator does. For precision work where it matters, the Hydration Calculator splits the leaven into its flour and water parts.

How do I scale a recipe up or down?

Pick your new flour weight, then multiply each ingredient's percentage against it — three quick solves in this calculator. Doubling 500 g of flour to 1000 g at 76% hydration means 760 g water; nothing else about the formula changes.

Want to know why this works? Every model and constant behind this calculator is explained, derived, and put to work in The Book of Sourjoe — the interactive book this calculator was built for.

These calculators are just the crust. Check out the Public Preview of the Sourjoe App — The Book of Sourjoe, recipes, and every baking tool in one place.

Questions? Comments? Send us a note at info@sourjoe.com.