Sourdough · Ratio Calculator
Sourdough Ratio Calculator
Scale the classic 1:2:3 dough ratio — 1 starter, 2 water, 3 flour — or any starter feeding ratio to exact grams, with overall hydration worked out for you.
1:2:3 from 100 g starter
600 g dough
Counting the starter, that is about 72% hydration. Change the ratio below.
Live calculator · updates as you type
Your ratio
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Common dough ratios
The 1:2:3 ratio is 1 part starter, 2 parts water, 3 parts flour by weight — a classic beginner formula at roughly 72% overall hydration once the starter is counted.
Sourdough ratio guide
The two ratios sourdough bakers mean
"Ratio" gets used two ways in sourdough. This calculator handles both — the dough mixing ratio you build a loaf from, and the feeding ratio you keep your starter alive with.
Starter : water : flour, by weight. 100 g starter, 200 g water, 300 g flour gives a 600 g beginner boule at about 72% overall hydration.
Starter : flour : water, by weight. Higher ratios dilute the culture more, slowing the peak and building a more sour flavour.
Every sourdough ratio is by weight in grams — a scale is essential, because flour, water, and starter all weigh differently. To turn a target hydration into weights instead, use the hydration calculator; to feed an existing jar to a set amount, use the feeding calculator.
Download the free Sourdough Baking Playbook
One printable PDF covering all six sourdough calculators — hydration, starter, feeding, levain, bulk fermentation, and discard.
Sourdough ratio questions
The 1:2:3 dough ratio, starter feeding ratios, and how to use them by weight.
The 1:2:3 ratio is a simple sourdough dough formula: 1 part sourdough starter, 2 parts water, and 3 parts flour, all by weight. For example, 100 g starter, 200 g water, and 300 g flour makes a 600 g dough. Counting the starter as flour and water, that lands at roughly 72% overall hydration — an approachable beginner boule.
Pick a mode. In dough mode, enter the amount of starter you have and choose or type a ratio (starter : water : flour); the calculator returns the water and flour to add, the total dough weight, and the overall hydration. In feeding mode, enter the starter you are keeping and a feeding ratio (starter : flour : water) such as 1:1:1 or 1:5:5 to get the flour and water to feed.
For maintenance, 1:1:1 (equal starter, flour, water) peaks fast in about 3 to 5 hours at 24°C and keeps a mild flavour, while 1:5:5 dilutes the culture more, peaks in 10 to 14 hours, and builds a more sour profile for overnight schedules. For dough, the 1:2:3 mixing ratio is the standard starting point.
Always by weight, in grams. Sourdough ratios only work reliably with a scale, because flour and water have very different densities and starter is heavier than either. Volume measures (cups and spoons) drift too much for a ratio to hold, so weigh every part.
The 1:2:3 mixing ratio counts the starter as one whole part, but a 100% hydration starter is itself half flour and half water. This calculator factors that in when it reports overall hydration, so the percentage reflects the true flour and water totals, not just the added amounts.