How much should you feed your starter?

What a feeding ratio is

Sourdough bakers describe a feeding as three numbers: starter, flour, water, by weight. A 1:1:1 feeding adds as much flour and as much water as there is starter, which King Arthur Baking calls the minimum for a healthy starter. Larger ratios such as 1:4:4 or 1:10:10 dilute the starter more, and it takes longer to peak. This calculator turns the ratio and the amount you want into grams, so you do not have to work out fractions at the counter.

The method

Everything you want in the jar after feeding, the amount for the recipe plus the amount you keep, is the starter plus the flour plus the water. If the flour is a times the starter and the water is b times the starter, that total is the starter times (1 + a + b), so the starter you take from the jar is the total divided by (1 + a + b). Flour and water are a and b times that. This is our own arithmetic, not a published formula. If your starter is not at 100% hydration, the calculator splits it into flour and water first so the hydration of the result is right. In recipe mode, the levain is the percentage of all the flour in the dough, and what is added to the dough is the total flour minus the levain’s flour and the total water (flour times hydration) minus the levain’s water.

Worked example

A recipe calls for 200 g of starter and you want to keep 50 g. The total is 250 g. At 1:1:1 you take 83.3 g of starter and add 83.3 g of flour and 83.3 g of water. At 1:5:5 you take only 22.7 g of starter and add 113.6 g of each. Both give 250 g at 100% hydration; the second has less starter to begin with and peaks later. Now a recipe: 500 g of flour, 75% hydration, a levain of 20% of the flour at 100% hydration. The levain weighs 100 g, holding 50 g of flour and 50 g of water. The dough needs 450 g more flour and 325 g more water, and weighs 875 g in all. To build that levain at 1:4:4 and keep 20 g, take 13.3 g of starter and add 53.3 g each of flour and water.

Common mistakes and limits

• Measuring by volume. King Arthur gives ratios by weight. A cup of flour changes with how it is packed, so a scale is the only way to feed at an exact ratio.
• Assuming the starter is at 100%. A stiff or runny starter changes the hydration of every feeding. Enter your real starter hydration, or the dough you build from it will be wetter or drier than the recipe expects.
• Comparing levain percentages across recipes. Some bakers divide by the flour added to the final dough, some by the total flour including the levain’s own, and the same levain can give very different percentages depending on the definition. We use the weight of the levain over all the flour.
• Trusting the clock over the jar. The peak times are from one baker’s trials at 78 °F. A cooler room or a young starter is slower; watch for the starter to double and bubble throughout, as King Arthur describes.
• Forgetting the part you keep. If you use all of the starter in the recipe, there is nothing to feed next time. Leave something in the jar; the “keep for next time” box does that arithmetic.

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

The numbers are starter : flour : water by weight. King Arthur Baking explains that 1:1:1 means equal weights, so 100 g of starter gets 100 g of flour and 100 g of water, and that this is a 100 percent hydration starter. At 1:5:5 you add five times the starter's weight in flour and water, so a small amount of starter makes a large batch: for 250 g of total starter you need only 22.7 g from the jar, 113.6 g of flour and 113.6 g of water.

How much starter do I need to make 200 g for a recipe?

Add what you need and what you want to keep for the next feeding, then divide by 1 plus the flour parts plus the water parts. For 200 g for the recipe and 50 g to keep, that is 250 g. At 1:1:1 you take 83.3 g of starter and add 83.3 g of flour and 83.3 g of water; at 1:5:5 you take 22.7 g and add 113.6 g of each. The calculator does this for any ratio, and a second box lets you use your own.

How long does a starter take to peak at each ratio?

King Arthur tested ratios at a warm 78 °F (about 26 °C) in a proofer. A 1:1:1 starter usually peaked after about 4 to 6 hours and was ready to feed again after about 12; a 1:2:2 starter peaked and doubled at about 8 hours; a 1:4:4 starter was fully doubled and peaked at about 12 hours, so feeding it before bed gives a starter ready to bake the next morning. Higher ratios such as 1:8:8 or 1:10:10 stretch the time between feedings, possibly to once a day, but the article gives no timings for them. A cooler kitchen or a weaker starter takes longer; use these as a starting point and watch your own jar.

Does the feeding ratio change how the bread bakes?

According to King Arthur's baking trials, starters fed at different ratios did not perform differently in baking; the ratio mainly changes timing, so pick it to match when you want the starter ready.

How do I get the hydration of my starter right?

Hydration is the water weight divided by the flour weight. Equal parts by weight is 100%. If your starter is stiffer, enter its hydration (for example 50%) and the calculator accounts for the flour and water already in it: 100 g of a 50% hydration starter fed 1:1:1 (300 g in all) ends at 80% hydration, because the starter itself holds only a third of its weight as water. Feeding with unequal flour and water parts, or switching flours, will move the hydration too.

What is the levain percentage?

Here it is the weight of the levain divided by the weight of all the flour in the dough, counting the flour inside the levain. For 500 g of flour and a 20% levain you need 100 g: 50 g flour and 50 g water at 100% hydration, plus 450 g of flour and 325 g of water in the final dough for 75% overall hydration. Other writers divide by different totals, such as the flour added to the final mix, so a recipe saying 20% may not mean this 20%. Check the definition before you scale.

Sources: King Arthur Baking, “Baking trials: Testing different sourdough feeding ratios”, Hannah Dela Cruz, March 13, 2025 (feeding ratios by weight, 100 percent hydration, timings at 78 °F). We found no university extension page that gives feeding ratios, so the timings rest on that one baking-company test; the proportion arithmetic is our own. Related: the baker’s percentage calculator for the whole dough, the yeast converter and the high altitude baking calculator.