Baker’s math is a method of calculating ingredient weights in relation to the total flour weight, expressed as percentages.

This allows bakers to easily adjust recipes for different batch sizes while maintaining the proper ratios of starter, flour, and water.

Start with the weight of the loaf you would like to bake.

The dough weight in this calculator refers to the wet dough weight, typically 800g–1000g. Your finished baked loaf will weigh less than this.

Then input how many loaves you would like to bake.

The default settings use common amounts for each variable, which you can tweak based on the type of loaf you want.

Refer to the other FAQs for specifics on each input field.

Sourdough hydration is simply the ratio of water to flour in your dough, expressed as a percentage.

• Low (60–65%): tighter crumb, denser loaf.
• Medium (66–75%): balanced crumb and crust.
• High (75–85%+): large, irregular holes and an open crumb.

This calculator uses a salt-to-flour ratio expressed as a percentage. The baseline is 2%, but recipes typically range from 1.5% to 3%. Kosher or additive-free salt performs best.

Typically, use 10%–30% starter relative to flour. A good starting point is 20%.

The amount you choose affects fermentation speed and depends on your ambient temperature.

Starter hydration is the percentage of water relative to flour in your levain. It’s calculated the same way as dough hydration:

• Higher (>100%): looser levain, faster fermentation, milder flavor.
• Lower (<100%): stiffer levain, slower fermentation, tangier profile.

Best practice is to keep this at 100%.