Free tools
Free sourdough calculators
The baker's math behind a good loaf, without the scrap paper. Every tool here uses the same formulas as the Zymo app, works in your browser and needs no sign-up.
Bulk fermentation chart
How long bulk takes at your dough temperature, with a live time estimate.
Open the toolSourdough calculator
Flour, water, starter and salt for any loaf size and hydration.
Open the toolStarter feeding calculator
Exact grams for 1:1:1, 1:2:2, 1:5:5 or any feeding ratio.
Open the toolHydration calculator
True dough hydration, counting the flour and water in your starter.
Open the toolBaker's percentage calculator
Turn any recipe into percentages, then scale it to any size.
Open the toolSourdough schedule planner
Pick when you want bread. Get every step, timed backward, ready to print.
Open the tool
Take them with you
Every tool here, plus a starter that reminds you.
Zymo is the sourdough app behind these calculators. It tracks your starter, plans each bake step by step, scores a photo of your crumb and answers baking questions through Crumb, its baking guide.
- Starter feeding reminders
- Step-by-step bake plans with fold reminders
- Loaf scans with a score and tips for the next bake
Free to download. No account needed.
Get Zymo
This tool is better on your phone.
Zymo is the sourdough app that does this math for you, reminds you when your starter is hungry, times every stage of the bake and scores a photo of your crumb. Coming soon to iPhone and Android.
