What Is the Sourdough Starter Calculator?
The Sourdough Starter Calculator is a free online tool designed for home cooks and chefs who need quick, accurate calculations in the cooking and food preparation space. By entering your current starter to keep, flour ratio, water ratio, you get instant results including starter to keep, add flour, add water. No formulas to memorize, no spreadsheets to build — just enter your numbers and get the answer in seconds. Whether you're a beginner or experienced professional, this calculator saves you time and eliminates guesswork.
Why This Calculation Matters
Getting starter to keep right can make the difference between success and costly mistakes. In cooking and food preparation, small errors compound quickly. Manual calculations are error-prone and time-consuming, especially under pressure. This calculator applies proven formulas used by home cooks and chefs worldwide, giving you confidence that your numbers are correct. Use it to perfect your recipes with precision and avoid common pitfalls that trip up beginners.
When Should You Use This Calculator?
This tool is most useful when you know your current starter to keep and need to find the right starter to keep. It's also great for quick estimates before committing to a decision, and to double-check manual calculations or professional quotes, and when comparing different scenarios side by side. Bookmark this page and come back whenever you need a fast, reliable answer — the calculator is always free and requires no signup.
Sourdough Starter Feeding Calculator
Sourdough Feeding Ratio Guide
How feeding ratios affect rise time and flavor at room temperature (75°F / 24°C).
| Ratio (S:F:W) | Rise Time | Flavor Profile | Best For |
|---|---|---|---|
| 1:1:1 | 4-6 hours | Tangy, strong | Daily baking, quick turnaround |
| 1:2:2 | 6-8 hours | Mildly tangy | Twice-daily feeding, evening levain |
| 1:3:3 | 7-10 hours | Balanced | Overnight levain build |
| 1:5:5 | 8-12 hours | Mild, complex | Overnight levain, artisan bread |
| 1:8:8 | 10-14 hours | Very mild | Cold kitchen, slow fermentation |
| 1:10:10 | 12-16 hours | Mild, wheaty | Very slow builds, stiff starters |
| 1:1:1 (cold) | 12-24 hours | Tangy | Fridge retard after feeding |
| 1:5:5 (cold) | 24-48 hours | Complex, mild | Multi-day cold fermentation |
How to Use This Calculator
- Enter Your Current Starter to Keep (g): Start by entering your current starter to keep — this is the primary input for the calculation.
- Fill In Additional Details: Complete the remaining fields: flour ratio, water ratio, target total weight — optional, target starter hydration %. Each value refines the calculation for greater accuracy.
- Click Calculate: Hit the Calculate button to run the numbers. Results appear instantly below.
- Review Your Results: Check your starter to keep, add flour, add water. Use these figures to inform your next decision or compare against alternative scenarios.
How It Works
Sourdough starter feeding ratios determine how much flour and water to add relative to the amount of starter you keep. The ratio affects fermentation speed, flavor, and rise timing.
The basic rule:
- 1:1:1 (starter:flour:water) — fast rise, good for daily baking. Peaks in 4-6 hours at 75°F.
- 1:2:2 — moderate rise, mild flavor. Peaks in 6-8 hours. Good for overnight levains.
- 1:5:5 — slow rise, more developed flavor. Peaks in 8-12 hours. Great for timing overnight bakes.
- 1:10:10 — very slow rise. Peaks in 12-16 hours. Best for cold environments or less-active starters.
Higher ratios (more flour and water relative to starter) produce a milder, slower-rising starter. Lower ratios produce a faster, more sour starter. Adjust your ratio to match your baking schedule.
Tips & Considerations
- Double-check your current starter to keep before calculating — even small input errors can significantly change your results.
- Run the calculator with different values to compare scenarios and find the optimal approach for your situation.
- Pay attention to both starter to keep and add flour — they work together to give you the full picture.
- Bookmark this page for quick access next time you need to perfect your recipes.
- If you're unsure about your target starter hydration %, start with a conservative estimate and adjust from there.
Frequently Asked Questions
What does 1:1:1 feeding ratio mean?
1:1:1 means equal parts starter, flour, and water by weight. If you keep 50g starter, add 50g flour and 50g water. This is the most common home baker ratio and produces a fast-rising starter.
How often should I feed my sourdough starter?
At room temperature (68-75°F), feed once or twice daily. In the refrigerator, feed once a week. The key is feeding before the starter fully collapses — ideally when it has doubled and just starts to recede.
What is the best ratio for sourdough bread?
For a levain used in bread, 1:5:5 is popular because it gives you 8-12 hours of slow, flavor-developing fermentation — perfect for mixing an overnight levain to bake with in the morning.
What do I do with sourdough discard?
Sourdough discard can be used in pancakes, waffles, crackers, pizza dough, muffins, banana bread, and many other recipes. Unfed discard adds tang and tenderness without needing to be active.
What hydration should my starter be?
Most starters are 100% hydration (equal flour and water by weight). This is easiest to maintain and most recipes assume it. Some bakers keep a stiff starter (60-80%) for milder flavor or an Italian-style lievito madre.
How do I know my starter is ready to use?
A ready starter has doubled in volume, has a domed top with visible bubbles, smells pleasantly tangy, and passes the float test (a spoonful floats in water). It should be used at peak rise, before it starts collapsing.