Ingredient % = ingredient weight ÷ flour weight × 100. Flour is always 100%, so the formula adds up to more than 100. To go backward from a dough weight, divide by the sum of the percentages: 1,800 g of dough at 171% needs 1,800 ÷ 1.71 = 1,053 g of flour.
Baker's percentage is taught in every bread and pastry course because it makes a formula independent of batch size. The problems come in a predictable order — find the percentage, find the grams, work back from a dough weight — and then add the complications real bakeries have: two flours, a preferment, liquids that are not water, and recipes written in cups. Each level below has worked answers. The baker's percentage calculator does the same arithmetic if you want to check your own numbers.
The Three Formulas
Ingredient % = ingredient weight ÷ total flour × 100
Ingredient weight = total flour × ingredient % ÷ 100
Total flour = dough weight ÷ (sum of percentages ÷ 100)
Everything must be in the same weight unit. Grams make the arithmetic easiest; ounces work as long as nothing is in cups.
Level 1: Percentages From a Recipe in Grams
A bread recipe uses 800 g bread flour, 560 g water, 16 g salt and 8 g instant yeast. Write it in baker's percentages.
Flour = 100%. Water = 560 ÷ 800 × 100 = 70%. Salt = 16 ÷ 800 × 100 = 2%. Yeast = 8 ÷ 800 × 100 = 1%. Total: 173%.
A brioche uses 500 g flour, 250 g eggs, 250 g butter, 60 g sugar, 10 g salt and 7 g instant yeast. What are the percentages?
Eggs 250 ÷ 500 = 50%, butter 50%, sugar 60 ÷ 500 = 12%, salt 2%, yeast 7 ÷ 500 = 1.4%. Total 215.4%.
A useful habit: check the salt first. It is close to 2% in nearly every bread, so a result of 4% or 0.5% usually means a misread recipe.
Level 2: Grams From Percentages and a Flour Weight
A formula is 100% flour, 65% water, 2% salt and 1.5% yeast. You have 1.5 kg of flour. How much of each?
Water = 1,500 × 0.65 = 975 g. Salt = 1,500 × 0.02 = 30 g. Yeast = 1,500 × 0.015 = 22.5 g.
A 1,000 g batch of flour is mixed at 65% hydration. The baker wants 70%. How much more water?
At 65%: 650 g. At 70%: 700 g. Add 50 g. Each hydration point is 1% of the flour — 10 g here.
Level 3: Working Back From a Dough Weight
This is the problem that matters in a bakery, because orders are in loaves and rolls, not grams of flour.
You need 12 dinner rolls of 60 g. The formula is 100% flour, 60% water, 2% salt, 1.5% yeast, 8% butter and 6% sugar. How much of each ingredient?
Dough: 12 × 60 = 720 g. Sum of percentages: 100 + 60 + 2 + 1.5 + 8 + 6 = 177.5%.
Flour = 720 ÷ 1.775 = 405.6 g. Water = 405.6 × 0.60 = 243.4 g. Salt 8.1 g, yeast 6.1 g, butter 32.5 g, sugar 24.3 g. Check: the six weights add back to 720 g.
Two 900 g loaves of lean bread (100% flour, 68% water, 2% salt, 1% yeast). Allow 2% extra for dough left in the bowl.
Dough: 1,800 × 1.02 = 1,836 g. Sum: 171%. Flour = 1,836 ÷ 1.71 = 1,073.7 g.
Water 1,073.7 × 0.68 = 730.1 g. Salt 21.5 g. Yeast 10.7 g.
The most common wrong answer at this level is multiplying 1,800 by 0.68 to get the water. That treats the water as 68% of the dough, which would make a very different bread.
Level 4: Two Flours and a Preferment
A loaf uses 700 g bread flour, 300 g whole wheat flour and 750 g water. What are the percentages?
Total flour = 1,000 g = 100%. Bread flour 70%, whole wheat 30%, water 750 ÷ 1,000 = 75%.
A poolish of 200 g flour, 200 g water and a pinch of yeast ferments overnight. The final dough adds 800 g flour, 500 g water, 20 g salt and 5 g yeast. What is the hydration, and how much of the flour is pre-fermented?
Total flour = 200 + 800 = 1,000 g. Total water = 200 + 500 = 700 g. Hydration = 70%. Salt = 20 ÷ 1,000 = 2%.
Pre-fermented flour = 200 ÷ 1,000 = 20%. Counting only the final-dough flour would give 500 ÷ 800 = 62.5% — a stiffer dough than the one actually in the bowl.
Level 5: Hydration When the Liquid Is Milk
Milk, eggs and butter are not pure water. Whole milk is about 88% water, whole egg about 76% and butter about 16% (USDA FoodData Central).
A soft roll dough uses 500 g flour, 320 g whole milk, one large egg (50 g out of the shell) and 40 g butter. What is the milk's baker's percentage, and what is the true hydration?
Milk = 320 ÷ 500 = 64%.
Water carried in: milk 320 × 0.88 = 281.6 g, egg 50 × 0.76 = 38 g, butter 40 × 0.16 = 6.4 g. Total 326 g. True hydration = 326 ÷ 500 = 65.2%.
Here the egg and butter almost exactly make up for the water missing from the milk. Drop the egg and butter and the true hydration falls to 56% even though the milk is still "64%".
Level 6: A Recipe Written in Cups
A recipe calls for 3 cups bread flour, 1¼ cups water, 8 g salt and one 7 g packet of instant yeast. Write it in baker's percentages.
Convert first: bread flour at 130 g per cup = 390 g; water at 240 g per cup = 300 g.
Water = 300 ÷ 390 = 76.9%. Salt = 8 ÷ 390 = 2.1%. Yeast = 7 ÷ 390 = 1.8%.
The answer is only as good as the cup conversion. Scooped flour can weigh 150 g a cup, which would bring the same recipe down to 67% hydration — the reason bakers weigh. The cups to grams converter lists the weights used here.
Quick Reference
| You know | You want | Do this |
|---|---|---|
| Ingredient grams + flour grams | Baker's % | ingredient ÷ flour × 100 |
| Baker's % + flour grams | Ingredient grams | flour × % ÷ 100 |
| Baker's % + dough weight | Flour grams | dough ÷ (sum of % ÷ 100) |
| Pieces × weight each | Dough weight | multiply, then add 1–3% for bench loss |
| Milk, egg or butter grams | Water they add | × 0.88, × 0.76, × 0.16 |
Common Mistakes
Dividing by the total dough. Baker's percentage is always over flour. A dough that is 40% water by total weight is about 70% in baker's percentage.
Forgetting the flour in a starter or poolish. Both the flour and the water inside a preferment count toward the totals.
Multiplying the dough weight by an ingredient's percentage. Find the flour first, then multiply the flour by each percentage.
Rounding small amounts to whole grams. In a 400 g flour batch, 1.5% yeast is 6 g; at 0.2% it would be 0.8 g, and rounding that to 1 g is a 25% error.
More Practice
The complete culinary math guide collects the other problem types that sit alongside baker's math — recipe conversion factors, cost per serving, food cost percentage and yield percentage. The kitchen math problem generator makes fresh practice problems with the working shown.
Frequently Asked Questions
A dough has 800 g of flour and 560 g of water. What is the water's baker's percentage?
560 ÷ 800 × 100 = 70%. Every ingredient is divided by the flour weight, not by the total dough weight.
How do you find the flour weight when you know the total dough weight?
Add every percentage in the formula, write the total as a decimal and divide the dough weight by it. Two 900 g loaves at 171% need 1,800 ÷ 1.71 = 1,053 g of flour, or 1,074 g with a 2% allowance for dough lost to the bowl.
Does the flour in a poolish or starter count in baker's percentage?
Yes. Total flour is the preferment's flour plus the final dough's flour, and the same goes for water. A 200 g/200 g poolish mixed with 800 g flour and 500 g water is 1,000 g flour and 700 g water — 70% hydration.
Why does a baker's percentage formula add up to more than 100%?
Flour on its own is 100%, and every other ingredient is added on top as a share of the flour. A lean bread of 100% flour, 68% water, 2% salt and 1% yeast totals 171%.