Sourdough Starter Feeding Ratio Calculator
Pick a ratio, enter how much starter you're keeping, and this calculator gets you exact flour and water amounts. Works whether you're feeding your everyday starter or building up enough for a specific recipe.
Common feeding ratios
| Amount | |
|---|---|
| Starter to keep back | n/a |
| Water to add | 100g |
| Total after feeding | 250g |
| This feeding's hydration | 100% |
| Discard | n/a |
A 1:2:2 feed at typical room temperature (72-75°F) usually peaks in about 6-8 hours. This varies with your starter and kitchen temperature.
| Stage | Starter in | + Flour | + Water | = Total |
|---|
Each stage's total becomes the next stage's starting starter. This is the same pattern used for building up a large levain for panettone or other big holiday bakes, not just everyday maintenance.
How this is calculated
The ratio numbers are read as starter : flour : water, always in that order, always by weight. To feed: flour to add = starter weight × flour parts, water to add = starter weight × water parts. If you need a specific total amount instead of starting from a fixed starter weight, the calculator works backward: it divides your target by the total number of parts (1 + flour parts + water parts) to figure out how much starter to keep back first.
On the ratio order: most sources, including King Arthur Baking's own reference on the topic, confirm starter : flour : water. A small number of sources use a different order, which is worth knowing if a chart you've seen elsewhere doesn't match numbers here.
Peak time by ratio (approximate, temperature-dependent)
| Ratio | Approx. peak @ 72-75°F | Best for |
|---|---|---|
| 1:1:1 | 4-6 hours | |
| 1:2:2 | 6-8 hours | |
| 1:3:3 | 6-10 hours | |
| 1:5:5 | 10-14 hours |
Frequently asked questions
What does a sourdough feeding ratio mean?
What's the best feeding ratio for most starters?
How often to feed sourdough starter in fridge?
1:5:5 vs 1:1:1, which should I use?
How this is checked. The starter:flour:water ratio order and the peak-time ranges above are cross-checked against multiple independent sourdough references, including King Arthur Baking's own reference on feeding ratios. Peak times are approximate and will shift with your specific starter, flour, and kitchen temperature. Treat them as a starting point, not a promise.