Baker’s percentages explained

Flour is 100%. Every other ingredient is a percent of the flour, not of the whole dough. Two percent salt on 1000 g of flour is 20 g of salt. On 800 g of flour it is 16 g. You do not recalculate the salt against the water, and you do not recalculate it against the finished weight. The flour is the base on purpose, because a dough’s water and salt are chosen relative to the flour that has to carry them.

Dough weight = flour × (100 + water% + salt% + oil% + sugar% + yeast%) ÷ 100. That is the whole formula when the leaven is commercial yeast and nothing is hiding inside a starter. Scaling a batch means changing the flour, then multiplying. The percentages stay. The grams move together, which is what you want if last week’s dough was right and this week’s dinner is larger.

A worked batch from flour

Eight hundred grams of flour at 65% water, 2.5% salt, and 0.3% instant yeast, with no oil and no sugar, has a formula total of 167.8. Flour is the 100. Water contributes 65, salt 2.5, and yeast 0.3. Dough weight is 800 × 167.8 ÷ 100. Water is 800 × 0.65. Salt is 800 × 0.025. Yeast is 800 × 0.003. None of those lines depends on the others. Raising the salt does not shrink the water. It only adds weight to the dough.

The calculator returns 520 g water, 20 g salt, and 2.4 g instant yeast. The dough weighs 1,342 g. Open this 800 g example and change one percentage. The other gram weights should sit still, and the dough weight should move by exactly the ingredient you changed.

The same formula, scaled

One and a half times the flour is 1200 g. The percentages do not get multiplied again. Water is still 65% of whatever the flour is. People sometimes scale the water by 1.5 and also nudge the percentage, and then they cannot tell which change they tasted. Keep the percentage fixed when you only meant to change the batch size.

At 1200 g of flour the same formula is 780 g water, 30 g salt, and 3.6 g yeast, and the dough weighs 2,014 g. That dough weight is 1.5 times 1,342 g, because every ingredient scaled with the flour. If it is not, a percentage was edited along the way.

Starting from the dough you want

Sometimes the constraint is the weight of the dough, not the bag of flour. A 1000 g dough at the same 65% water, 2.5% salt, and 0.3% yeast has to be solved backwards. Flour = dough weight × 100 ÷ (100 + water% + salt% + oil% + sugar% + yeast%). Then each ingredient is that flour times its own percentage. The pizza calculator does this for a set of balls: four balls at 250 g is a 1000 g dough, and the flour falls out of the percentages.

For 1000 g of dough at those percentages, the flour is 596 g, the water is 387 g, the salt is 14.9 g, and the instant yeast is 1.79 g. Add those weights back up and you are at the 1000 g you asked for, apart from rounding on the screen. The calculator keeps the exact target and rounds only what it displays.

Yeast type is part of the percentage

0.3% instant yeast is the weight of instant yeast, not a universal “leaven percent.” The same leavening expressed as fresh yeast is a larger weight, because fresh yeast is mostly water. This site uses King Arthur’s professional factors: instant = fresh × 0.33, and active dry = fresh × 0.40. If a formula says 0.3% and you change the menu from instant to fresh without changing the percentage, you have changed the dose a lot. Either convert the weight and type the new percentage, or use the conversion calculator and read both numbers before you mix.

King Arthur’s home-baking guidance sometimes treats active dry and instant as equal on a long rise. This site still shows the professional factors, and it says so on the conversion page. Pick one convention and keep it with the formula you are scaling. Mixing the two conventions is how a doubled batch gets a different yeast than the original.

Sourdough, worked

Flour and water inside the starter belong to the flour and the water. Inoculation on this site means starter weight divided by total flour. Twenty percent inoculation on 1000 g of flour is 200 g of starter. At 100% starter hydration, 100 g of that is flour — 10% prefermented flour — and 100 g is water. You do not add the starter on top of the water percent. The 70% already includes the starter’s water.

So a 1000 g flour dough at 70% water, 2% salt, and that starter is 900 g flour to weigh, 600 g water to pour, 20 g salt, and 200 g starter. True hydration stays 70%. Prefermented flour is 10%. The calculator shows both the totals and the smaller set of ingredients you actually put on the scale.

A small table of the same idea

Each row is one ingredient against 1000 g of flour. Nothing in the table is a recommended formula. It is the multiplication you do for any percentage you have already chosen.

Write the formula as percentages, scale the flour, and weigh what the multiplication says. If a dough you already trust disagrees with a default on this site, keep your dough. The calculator is there to scale it and to show the gram that moved when you changed a percentage.