Free sourdough tools
Sourdough calculators: ten free tools for better bread
Every calculator on this page is free, runs in your browser, and needs no sign-up. They exist to answer the questions that actually come up mid-bake: how long will this dough take to rise, what temperature should my water be, how much levain do I build, and when do I need to start so the loaf isn’t coming out of the oven at 3 a.m. Start with the Schedule Builder if you’re planning a bake, or jump straight to the tool that solves today’s problem.
⚡ Sourdough Schedule Builder
Enter your start time and dough details and get a complete timeline for the whole bake — leaven build, mix, folds, bulk fermentation, shaping, proof, bake, and cool, each on the clock. It’s powered by the same calibrated rise model as the Rise Time Calculator, and it’s the tool bakers ask for most.
Rise Time Calculator
The flagship. Estimate bulk fermentation and proof time from dough temperature, inoculation, hydration, and salt — including cold-retard planning and tang control. Stop poking the dough and guessing; put a number on it.
Bread Recipe Hydration Calculator
Most hydration numbers lie, because they ignore the water hiding in your leaven. This calculator computes true dough hydration from every liquid in the recipe, so 75% actually means 75% — with a practical reference chart for what different hydrations feel like.
Baker’s Math Calculator
The fastest way to scale or adjust a formula. Enter any two of flour weight, ingredient weight, and baker’s percentage, and it solves for the third.
Desired Dough Temperature (DDT) Calculator
Dough temperature drives everything downstream, and water is the lever you control. Enter your target dough temperature plus room, flour, and leaven temperatures and a friction factor, and get the exact water temperature for your mix.
Desired Water Temperature Calculator
The DDT calculator’s practical partner: it tells you how much boiling water and tap water to mix to hit a specific amount of water at a specific temperature — no thermometer juggling over the sink.
Leaven Calculator
Work backward from your bake. Tell it how much leaven you need and at what hydration, and it calculates exactly how much flour and water to add to your seed starter.
Sourdough Starter Recipe Calculator
Design a starter feeding from water, two flours, and other liquid ingredients, and see the resulting hydration instantly — useful for maintaining a starter or converting it to a new hydration.
Rise Factor Calculator
Put a number on your oven spring. From measured loaf dimensions, estimate baked-and-cooled volume, specific volume, density, and a rise score you can track from bake to bake.
Baking Unit Converter
Weight, volume, and oven temperatures, with ingredient-aware cup-to-gram conversions — because a cup of flour and a cup of honey are not remotely the same weight.
How they fit together: These tools aren’t standalone tricks — they’re the math behind a repeatable process. The Baker’s Process chapter walks through where each one fits in a real bake: DDT at mixing, rise time through bulk and proof, the Schedule Builder wrapping it all in a timeline. If you’re new to sourdough, Start Here is the front door.
Want the full experience? The calculators are free forever. The Sourjoe public preview adds The Book of Sourjoe, guided lessons, and recipes around them — or jump to sign-up options.