Baker's percentages write every ingredient as a percentage of the flour weight, and the flour is always 100%. To cost with them, you turn the formula into a cost per kilo of dough once: multiply each percentage by that ingredient's price per kilo, add the results, and divide by the total of the percentages. From then on, any batch costs kilos of dough × cost per kilo, and any loaf costs its dough weight × the same number.
What baker's percentages are
A normal recipe lists grams: 1,000 g flour, 750 g water, 20 g salt. A baker's percentage formula lists the ratio to the flour: flour 100%, water 75%, salt 2%. If you use two flours, say white and wholemeal, together they make 100%.
The sum of all the percentages tells you how much dough each kilo of flour gives you. A formula that adds up to 197% gives 1.97 kg of dough per kilo of flour.
For costing, this has two advantages over a recipe in grams:
- It does not depend on batch size. The cost per kilo of dough is the same whether you mix 2 kg or 25 kg of flour. It only changes when prices or the formula change.
- It shows what drives the cost. With every ingredient on the same base, you see at once which one takes most of your money.
Turning the formula into cost per kilo of dough
- Get each ingredient's price per kilo. A 25 kg sack of bread flour at $30.00 is $1.20 per kilo. If grams, pounds and pack sizes get in the way, see units and conversions for costing.
- Multiply each percentage, as a decimal, by its price per kilo. That is what the ingredient costs per kilo of flour you use.
- Add up that column. It is the cost of all the dough one kilo of flour makes.
- Divide by the total percentage as a decimal. That is your cost per kilo of dough.
Use the prices on your latest invoice, not the ones from three months ago.
Worked example: a sourdough loaf
A plain sourdough. The levain is equal parts flour and water, so its cost per kilo is half the flour price.
| Ingredient | Baker's % | Price per kg | Cost per kg of flour |
|---|---|---|---|
| Bread flour | 100% | $1.20 | $1.200 |
| Water | 75% | $0.00 | $0.000 |
| Salt | 2% | $1.00 | $0.020 |
| Levain | 20% | $0.60 | $0.120 |
| Total | 197% | $1.340 |
Each kilo of flour gives 1.97 kg of dough that costs $1.34.
Cost per kilo of dough: 1.340 ÷ 1.97 = $0.680
That one number answers everything else:
- One loaf with 900 g of dough: 0.900 × 0.680 = $0.61 in ingredients.
- A batch of 10 loaves: you need 10 × 900 g = 9 kg of dough. The flour is 9 ÷ 1.97 = 4.569 kg, and the rest comes from the percentages: water 4.569 × 0.75 = 3.427 kg, salt 91 g, levain 914 g. The cost is 9 × 0.680 = $6.12, without adding up every ingredient again.
If the 900 g of dough comes out of the oven at 780 g, the cost per loaf does not change. You paid for the 900 g that went in.
Which ingredient drives the cost
Divide each line by the $1.34 total:
- Flour: 1.20 ÷ 1.34 = 89.6%
- Levain: 0.12 ÷ 1.34 = 9.0%
- Salt: 0.02 ÷ 1.34 = 1.5%
In a lean dough, flour is nearly the whole cost, so its price is the one to watch. If flour goes from $1.20 to $1.40 a kilo, the levain goes to $0.70 a kilo too. The flour column becomes 1.40 + 0.14 + 0.02 = $1.56, the kilo of dough 1.56 ÷ 1.97 = $0.792, and the loaf 0.900 × 0.792 = $0.71. That is ten cents more per loaf, $1.00 more per batch of ten.
It changes when you add expensive extras. Say you make a seeded version with 10% of a seed mix at $8.00 a kilo:
- Seeds: 0.10 × 8.00 = $0.800
- New total: 1.340 + 0.800 = $2.140
- New total percentage: 197% + 10% = 207%
- Cost per kilo of dough: 2.140 ÷ 2.07 = $1.034
- Loaf with 900 g of dough: 0.900 × 1.034 = $0.93
The seeds alone are 0.80 ÷ 2.14 = 37.4% of the ingredient cost, and the loaf costs 32 cents more. If both loaves sit on the shelf at the same price, you now know which one pays you less.
What baker's percentages leave out
The cost per kilo of dough is ingredients only. To know what a loaf really costs you, four things are missing:
- Waste. Dough stuck to the bench, misshapen loaves, a tray that got too dark. If one of the ten loaves cannot be sold, the ingredient cost per sellable loaf is 6.12 ÷ 9 = $0.68, not $0.61.
- Your time mixing, folding, shaping and baking.
- The oven: gas or electricity for each bake.
- The bag or packaging, if you use one.
The guide on how to calculate the cost of a loaf of bread adds all of that step by step. If you need to take a recipe in grams to another size without breaking the cost, see how to scale a recipe or use the recipe scaler, which scales a recipe to N portions.
When to recalculate
- When the price of flour or fat changes. Those lines move the result most.
- When you change the formula, even a few points of hydration or sugar.
- When you change supplier or pack size (a 25 kg sack instead of 5 kg bags).
You do not need to recalculate because you changed the piece weight or the batch size. That is the whole point of the method.
Do it with the calculator
In the food cost calculator, enter each ingredient with what you paid for it and the dough weight per piece. It gives you the cost per loaf and lets you add your time, the oven and the bag to reach the loaded cost.
Frequently asked questions
Do I count the water in the cost?
Tap water costs close to nothing per kilo, so you can enter $0.00. Its percentage still goes into the total, because it adds to the dough you get.
How do I handle levain or a preferment?
Treat it as its own ingredient with its own cost per kilo, worked out from the flour and water inside it. Purists fold its flour into the 100%; for costing, what matters is that its cost is right.
Do I need to recalculate if I change the loaf size?
No. The cost per kilo of dough stays the same; you just multiply it by the new dough weight per piece. Recalculate when prices or the formula change.
Should I use the raw dough weight or the baked weight?
The raw weight, the dough you scale and shape. The loaf loses weight in the oven, but you paid for all the dough that went in.