Sourdough Calculator

How the Math Works

Baker’s percentages describe every ingredient as a share of the flour weight, so flour is always 100%. With 500 g of flour and a target of 75% hydration, the water is 375 g. Salt at 2% comes to 10 g, and starter at 23% comes to 115 g.

The total dough weight is the four weights added together. In that example it is exactly 1000 g, which makes the percentages easy to check. If you only know the total dough weight, switch to that option and the calculator works backward to the flour.

The starter builder takes the ripe starter your recipe needs and divides it by your feeding ratio. At 1:5:5 the total is split into eleven parts, one of existing starter and five each of flour and water. For 200 g of ripe starter, keep about 18 g of the old starter, then add 91 g of flour and 91 g of water.

The bake-day planner works backward from the time you want the bread out of the oven. It sets the final proof, the shaping, the mix and the starter feeding ahead of that time, and your kitchen temperature moves the hours, since dough ferments faster in a warm kitchen. Tick the overnight box if you plan to proof the shaped loaf in the fridge.

Quick Questions

What hydration should I start with?

The calculator opens at 75%. Higher hydration tends to give a stickier dough with a more open crumb, and lower hydration is easier to shape. Change the number and every weight updates.

What does a 1:5:5 feeding ratio mean?

It is the weight of existing starter to flour to water. At 1:5:5 you feed 1 part starter with 5 parts flour and 5 parts water. A higher ratio takes longer to peak, and the starter builder shows an estimated ready time for your kitchen temperature.

How do I plan an overnight loaf?

Enter the time you want the loaf out of the oven and pick your kitchen temperature. Tick the overnight fridge box if the shaped loaf will proof in the fridge. The planner then lists when to feed the starter, mix, shape and bake.