Baker’s Percentage Calculator

How baker’s percentages work

In a bread formula every ingredient is written as a percentage of the total flour weight, with flour itself fixed at 100%. A classic sourdough might read: flour 100%, water 70%, salt 2%, levain 20%. The percentages describe the dough itself, independent of batch size — which is what makes them so useful. Double the flour and every other gram amount doubles with it, and any two recipes can be compared at a glance.

Scaling up and down

The most common real-world use is working backwards from a target. Your banneton takes roughly a 950 g loaf, so how much flour do you start with? Divide the target dough weight by the sum of the percentages (here 1.92) and you get the flour weight; everything else follows. This calculator does both directions — give it flour and it builds the formula down the page, give it a dough weight and it solves for the flour first.

Sensible ranges

Salt almost always sits at 1.8–2.2% — below that bread tastes flat, above 2.5% fermentation slows noticeably. Levain typically runs 15–25% of the flour: more levain ferments faster and tips the flavour toward sour, less gives you a longer, more forgiving timeline. Water is the variable bakers argue about; see the hydration calculator for what the percentage actually means for handling and crumb.

One caution when comparing formulas: some recipes count the flour and water inside the levain toward the totals, and some do not. It rarely changes the bread much, but it explains why two “75% hydration” recipes can behave differently.