Sourdough starter feeding calculator

A feed of 1:2:2 means 1 part starter, 2 parts flour and 2 parts water, by weight. The bigger the feed, the longer the starter takes to rise and fall.

Warmth speeds it up: every 10°F colder roughly doubles the time. The range shown is where most starters land — yours may be faster or slower, and the app learns which.

It is ready at its peak: doubled or more, domed, full of bubbles. Watch the jar, not the clock.

At 75°F (24°C) a starter fed 1:1:1 is usually ready in 3½–6½ hours, 1:2:2 in 4½–8½ hours and 1:5:5 in 6–11½ hours. A cooler kitchen takes longer: 1:2:2 at 68°F (20°C) takes 7½–14 hours.

One part starter, two parts flour and two parts water, by weight. For 100 g of starter: 20 g starter + 40 g flour + 40 g water.

Use 1:1:1 when you want it ready soon, 1:2:2 for a normal day, and 1:5:5 overnight — at 70°F (21°C) it takes about 8½–16 hours, so it is ready when you wake up.

It has at least doubled, the top is domed or just starting to flatten, and it is full of bubbles. A rubber band around the jar at the starting level makes the rise easy to see.

Checked September 30, 2026. The figures are the bakers’; the model and the words are ours. Watch the dough, not the clock.

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