crumbmath is a small, independent site of free sourdough calculators. It is built and maintained by Muhammad Afzal, a web and conversion specialist who spends his working days making websites easier to use.
It exists because the arithmetic of sourdough is easy to get slightly wrong. Most online calculators ignore the flour and water inside the starter, or break when the starter and levain have different hydrations. The aim here is a handful of tools that handle those cases properly, explain their working, and are pleasant to use with floury hands.
How the tools are kept accurate
Every formula is published on its calculator page and on how we calculate. Each calculation is checked automatically against the worked examples shown on its page whenever the site is updated. If you find a mistake, please get in touch; corrections are made quickly and noted.
What crumbmath is not
It is not a recipe site or a baking course. Timings and textures depend on your flour, starter and kitchen, and no calculator can replace watching your dough.
Independence
crumbmath is not sponsored by any flour, equipment or baking brand. If the site later carries advertising or affiliate links, they will be disclosed on the pages where they appear and in the privacy policy.