Sourdough Starter Feeding Calculator
Feeding ratios are written starter : flour : water. Pick a ratio and how much you need, and get the exact grams — no discard guesswork.
Choosing a ratio
| Ratio | Peak time (21°C/70°F) | Best for |
|---|---|---|
| 1:1:1 | 3–5 hours | Reviving a sluggish starter, same-day bakes |
| 1:2:2 | 5–8 hours | Everyday maintenance |
| 1:3:3 | 6–10 hours | Milder flavour, stronger rise |
| 1:5:5 | 8–14 hours | Overnight feeds, less discard per bake |
Times assume a 100% hydration starter at about 21°C (70°F). Every 10°C warmer roughly halves the time; colder roughly doubles it.
How it works
The ratio's parts are all by weight. If you know the total you want, the starter portion is total ÷ (parts of starter + flour + water), then flour and water follow from their parts. If you're working from the starter you already have, each part is simply scaled up from it. Equal flour and water parts keep a 100% hydration starter at 100% hydration.
FAQ
Do I have to discard?
Only to keep the jar manageable. Using a larger ratio (1:5:5) means less discard relative to what you keep — or bake with the discard instead of binning it.
How do I know it has peaked?
It has roughly doubled, domed on top, and smells tangy but sweet. Once it flattens or sinks, it's past peak — still usable, just less lively.
Can I feed a stiff starter this way?
Yes — use unequal parts, like 1:2:1 for a stiff levain. The calculator handles any custom ratio, and the hydration calculator shows what it does to your dough.