It's Thursday night and Saturday wants 24 loaves.
Pick your loaf count and dough weight per loaf, and it runs the baker's math backward — total flour, water, salt, and levain to the gram, in whichever hydration camp you bake in. Everything stays in your browser.
The bake
Pricing
The day
The numbers here are yours to check. This page does arithmetic on what you type — it cannot see your recipe, your equipment or your batch.
For anything you will eat or sell as food, double-check it against your own process and your local rules. This page does maths, not food safety.
Want it to remember?
In MadeKeeper, that same Saturday bake pulls flour, salt, and starter feed out of your inventory automatically and drops the true cost per loaf into your ledger, right under what you charge for it at the market. See for cottage bakers or poke around the live demo. $19/mo for the whole back office, kept for as long as you stay. The shop stays free for cost a piece and one fair — no product cap. The tax packet, Etsy and Square, and more fairs are the $19.
Free sourdough math for market bakers
Straight answers on the math — including the parts bakers have never stopped arguing about.
Does the flour and water in my levain count toward hydration?
That's the oldest argument in sourdough math, and it's exactly why it's a toggle here instead of a hard-coded answer. The counted camp — our default — folds the levain's flour and water into the totals, so a 75% dough is truly 75%: on a two-loaf bake the calculator nets the levain's roughly 101.7 g of flour and 101.7 g of water out of your mix. The separate camp treats the levain as an ingredient on top, which means a "75%" formula with 20% levain at 100% hydration actually bakes out closer to 77% true hydration. Both camps sum back to the same dough weight, and your answer always names which camp it used — so when you swap formulas with another baker, you know whether you're speaking the same language.
How does it scale my 2-loaf formula to a 24-loaf market bake?
It runs backward from what you actually need: loaves times dough weight per loaf gives total dough, and since flour is the 100% in baker's math, total flour in the counted camp is dough divided by (1 + hydration + salt). Two 900 g loaves at the defaults — 75% hydration, 2% salt, 20% levain — come out to 1,016.9 g of total flour, split into a mix of 915.3 g flour, 661 g water, 20.3 g salt, and 203.4 g of levain. Scale to 24 loaves and the same division just gets bigger, about 12.2 kg of flour; the ratios never move, so Saturday's dough handles like Thursday's.
Why do my baked loaves weigh less than the dough I scaled?
Water bakes out, and how much depends on loaf size, your oven, and how dark you take the crust — bakers argue anywhere from 10 to 20%, so the calculator seeds 15% as a setting, not a fact. At 15%, a 900 g dough loaf lands near 765 g out of the oven. Weigh a few of your own baked loaves and set your real number once — your scale outranks anybody's default.
Are 75% hydration and 2% salt rules I'm supposed to follow?
They're conventions — the middle of where most home sourdough formulas sit, not correct answers. Salt at 2% of flour weight is the number bakers orbit, but plenty of formulas run leaner or saltier, and hydration is really a conversation between you and your flour — a thirsty whole-grain blend drinks more than a white bread flour at the same feel. Every default here is a setting, so change it once to match the formula you already trust and the whole bake, 2 loaves or 24, recalculates around it.