Sourdough Starter Feeding Calculator
Enter how much starter you keep and a feeding ratio to get the flour and water to add - or enter the amount your recipe needs and work backwards to tonight's feeding.
Results
- Flour to add
- 50 g
- Water to add
- 50 g
- Total after feeding
- 150 g
What the ratio means
A 1:1:1 feeding means equal parts starter, flour and water by weight. Larger ratios like 1:2:2 or 1:5:5 give the culture more food, slow acidification and buy time before the peak - useful when your baking window is hours away. The peak typically arrives sooner in warm rooms; adjust by feel, not just by clock.
Common feeding ratios
| Ratio | When to use it |
|---|---|
| 1:1:1 | Same-day bakes. Peaks in about 4-6 hours at room temperature. |
| 1:2:2 | A gentle slow-down; peak in roughly 6-8 hours. |
| 1:4:4 | Overnight or workday feeds. More food, slower acid build-up. |
| 1:5:5 | Long scheduling windows and building up a cold, mild starter. |
Frequently asked questions
What does 1:1:1 mean for sourdough starter?
Equal parts starter, flour and water by weight. Feed 50 g of starter with 50 g of flour and 50 g of water and you keep 150 g. Larger ratios like 1:2:2 keep less starter relative to food, which slows fermentation.
How much starter does a sourdough recipe need?
Most recipes use 10-25% of the flour weight as starter. Enter the amount your recipe lists and this calculator works backwards to the feeding you need tonight.
Should I keep a large starter?
No - a small kept amount (20-50 g) fed with a bigger ratio is easier to maintain and produces less discard. Build up to the recipe amount with one or two larger feeds before baking day.