Sourdough Starter Percentage for Pizza: Count Flour and Water

In this calculator, starter percentage means starter mass divided by total recipe flour, multiplied by 100. It does not mean the percentage of flour prefermented. A 15% starter dose at 100% starter hydration contains only 7.5% of total flour inside the starter.

Use the sourdough calculator to keep that definition consistent across the ingredient totals and final additions. Starter contributes both flour and water; its mass must not be added on top of already counted flour and water.

Start with 1,000 g total flour

At 15% starter mass, use 150 g starter. For a 100%-hydration starter, that is 75 g flour and 75 g water. At 65% final hydration:

Total flour = 1,000 g
Total water = 650 g
Starter = 150 g, containing 75 g flour + 75 g water
Fresh flour to add = 925 g
Fresh water to add = 575 g

Add salt and any other ingredients separately. Do not add 1,000 g fresh flour and 650 g fresh water as well as the starter: that would change both batch mass and hydration.

Other starter hydrations

For starter mass S and hydration H expressed as a percent:

Starter flour = S ÷ (1 + H/100)
Starter water = S − starter flour

A 150 g starter at 60% hydration contains 93.75 g flour and 56.25 g water. With the same master recipe, fresh additions become 906.25 g flour and 593.75 g water. The inoculation mass is unchanged, but the prefermented flour share is now 9.375%.

Check how an external recipe defines inoculation before transferring its number. Some recipes specify prefermented flour; others specify wet starter relative to fresh flour rather than all flour. Those bases require conversion, not copying the label alone.

How much starter should you choose?

Use a complete sourdough recipe as the starting point. Starter maturity, feeding history, temperature and dough formulation influence the schedule. The displayed 15% / 100% defaults are an accounting example, not a promise that the dough will be ready in a particular number of hours.

Observe the starter and dough over repeated batches. Changing the dose while also changing starter hydration and temperature makes the comparison hard to interpret. The commercial-yeast model is not used as an equivalent prediction for sourdough.

Read the output correctly

The master table’s flour and water totals include the starter contributions. The starter row identifies that included ingredient; it is not an extra mass to add to the totals. The final-mix table instead shows what to add to the measured starter.

If the dough weakens, read overproofing before adding more flour. A high starter percentage is not automatically better, healthier or more digestible.