Sourdough Calculator
Calculate exact sourdough bread ingredients with adjustable hydration and starter percentage. Recipes for country loaf, focaccia, sandwich bread, high-hydration, and discard pancakes.
Sourdough hydration is expressed as water weight ÷ flour weight. A standard white loaf is 70% hydration; a wholegrain or ciabatta can go to 80-85%. Starter is typically 20% of flour weight, salt 2%, and you need a 4-6 hour bulk ferment followed by cold retarding overnight.
Enter your flour weight or target loaves, we'll calculate water, salt, and starter.
Sourdough Calculator
The classic beginner sourdough, open crumb, crispy crust, tangy flavour.
500g makes ~1 loaf. 1000g makes ~2 loaves.
Your Recipe, Basic Country Loaf
Assumes 100% hydration starter (equal parts flour and water). The starter contributes both flour and water to the final dough.
| What to Measure | Grams | Volume |
|---|---|---|
| Bread flour | 450g | 3.8 cups |
| Water | 325g | 325ml |
| Active starter (100% hydration) | 100g | 0.4 cups |
| Fine sea salt | 10g | 1.7 tsp |
Total Dough
985g
Total Flour
500g
Hydration
75%
Starter
20%
Baker's Percentages (relative to total flour)
Basic Country Loaf, Instructions
Bulk Fermentation
4-6 hours at room temp (or 8-12 hours if cool kitchen)
Proof / Cold Retard
12-16 hours in fridge (cold retard)
Oven
250°C / 480°F with Dutch oven lid on for 20 min, then lid off for 20-25 min
Use a mix of 90% bread flour + 10% whole wheat for the best flavour and structure. Stretch and fold every 30 minutes during bulk ferment (4-6 sets). The dough should feel jiggly and airy when bulk is done.
Starter Feeding Ratios
Standard (1:1:1)
Equal parts starter, flour, water by weight. 50g each = 150g total.
When: Daily maintenance at room temp, or before baking (feed 8-12 hours ahead)
Strong feed (1:2:2)
50g starter + 100g flour + 100g water = 250g total. Slower rise, more developed flavour.
When: When you want a slower, more predictable rise. Good for overnight levains.
Stiff feed (1:2:1)
50g starter + 100g flour + 50g water = 200g. Thick, dough-like consistency.
When: For less sour flavour, or when fridge-storing starter between bakes.
Weak/rescue feed (2:1:1)
100g starter + 50g flour + 50g water. Heavy on starter.
When: When starter is sluggish and needs a boost. Feed twice daily until active.
Frequently Asked Questions
▶What hydration should my sourdough starter be?
100% hydration is standard, equal parts flour and water by weight (e.g. 50g flour + 50g water). This is what our calculator assumes. Some bakers use stiff starters (60-80% hydration) for less sour flavour, but 100% is easiest to maintain and most recipes expect it.
▶How do I know when bulk fermentation is done?
Look for: 50-75% volume increase, dough feels airy and jiggly (not dense), visible bubbles on the surface and sides, and the dough pulls away slightly from the container. Don't rely on time alone, temperature makes a huge difference.
▶What does 'cold retard' mean?
Cold retarding means putting shaped dough in the fridge (3-5°C / 38-41°F) for 12-36 hours. The cold slows fermentation, develops more complex flavour, makes the dough easier to score, and lets you bake on YOUR schedule. Most bakers shape in the evening and bake the next morning.
▶Why do I need a Dutch oven?
A Dutch oven traps steam during the first 20 minutes of baking. Steam keeps the crust soft so the bread can expand fully (oven spring), then forms a thin, crispy, blistered crust when the lid comes off. Without it, the crust sets too early and you get a flat, thick-crusted loaf.
▶Can I use all-purpose flour instead of bread flour?
Yes, but the result will be different. Bread flour (12-14% protein) gives more structure and chew. AP flour (10-12% protein) makes a softer, more tender crumb. For beginners, bread flour is more forgiving at higher hydrations. Many great bakers use a blend of both.
▶How much starter should I keep?
You only need about 50g of starter to maintain it. Feed with 50g flour + 50g water for 150g total. Use or discard the excess before each feeding. When you need more for a recipe, do a larger feed the night before (e.g. 50g starter + 150g flour + 150g water).
▶What's the difference between levain and starter?
They're essentially the same thing. 'Levain' (French) is a portion of starter that's been specifically fed and built up for a recipe. Some bakers maintain a rye starter but build a levain with bread flour for their recipe. The terms are often used interchangeably.
▶Why does my starter have liquid on top?
That's 'hooch', alcohol produced by the yeast when it runs out of food. It means your starter is hungry. Pour it off (or stir it back in for more sour flavour), then feed. If it happens daily, feed more often or keep it in the fridge.
▶Can I bake sourdough without a Dutch oven?
Yes. Use a baking stone/steel and create steam by: placing a tray of boiling water on the bottom rack, spraying the oven walls with water, or inverting a roasting pan over the bread for the first 20 minutes. Results won't be quite as good as a Dutch oven, but still excellent.
▶Is my data saved anywhere?
No. Everything runs in your browser. Nothing is sent to any server or tracked.
What Makes Sourdough Different?
Sourdough uses a wild yeast and bacteria culture (the "starter") instead of commercial yeast. This living culture ferments the dough over hours, much slower than instant yeast, producing organic acids that give sourdough its signature tangy flavour, chewy texture, and longer shelf life.
The slow fermentation also breaks down gluten and phytic acid, making sourdough easier to digest than commercial bread. Many people who struggle with regular bread find sourdough more tolerable.
Sourdough baking is part science, part intuition. Temperatures, timing, and flour types all matter, but once you understand the fundamentals, it becomes second nature.
How to Create a Sourdough Starter from Scratch
Day 1
Mix 50g whole wheat or rye flour + 50g water (room temp). Stir well. Cover loosely. Place somewhere warm (24-27°C / 75-80°F).
Day 2
You may see nothing, or a few bubbles. Discard all but 50g, add 50g flour + 50g water. Stir, cover.
Day 3
Bubbles should start appearing. It may smell sour or unpleasant, that's normal. Discard + feed same as Day 2.
Day 4-5
Activity increases. You should see the mixture rising and falling. Continue daily discard + feed. Switch to bread flour if you started with whole wheat.
Day 6-7
Starter should double in size within 4-8 hours of feeding. If so, it's ready to bake with! If not, keep feeding, some starters take 10-14 days.
Ongoing
Feed once daily at room temp, or once a week if stored in the fridge. Always feed 12 hours before you plan to bake.
The Float Test: Is Your Starter Ready?
Drop a small spoonful of fed starter into a glass of water. If it floats, it's active and ready to leaven bread. If it sinks, feed it again and wait 2-4 more hours.
The float test works because active starter is full of gas bubbles that make it buoyant. It should be tested at peak activity, when it has roughly doubled and the surface is domed, not collapsed.
Caveat: The float test isn't 100% reliable for all flour types. High-hydration starters or those made with 100% whole grain flour may not float even when active. In that case, rely on visual cues: doubling in size, lots of bubbles, domed surface, and a pleasant yeasty-sour smell.
Sourdough Hydration Explained
| Hydration | Dough Feel | Crumb | Best For |
|---|---|---|---|
| 65-70% | Firm, easy to handle | Tight, uniform | Sandwich loaves, bagels |
| 72-78% | Tacky, manageable | Open, moderate holes | Country loaf (beginner sweet spot) |
| 80-85% | Sticky, needs wet hands | Very open, large holes | Artisan loaves, ciabatta |
| 85%+ | Almost batter-like | Extremely open | Focaccia, pizza, advanced bakers only |
Important: Your starter's hydration matters too. Our calculator assumes a 100% hydration starter (equal parts flour and water by weight). If your starter is different, the calculations will be slightly off, but 100% is the most common and recommended ratio.
Sourdough Troubleshooting Guide
Loaf didn't rise (dense, flat)
Starter wasn't active enough (do the float test). Or bulk ferment was too short, the dough should have increased 50-75% in volume and feel airy. In a cold kitchen, bulk can take 8+ hours.
Bread is too sour
Reduce fermentation time. Use a higher starter-to-flour ratio (so it rises faster). Use less whole grain flour. Keep the dough warmer during bulk ferment, warmth favours yeast (mild) over bacteria (sour).
Bread is not sour enough
Extend the cold retard to 24-36 hours. Use more whole grain flour. Use a smaller amount of starter (so fermentation takes longer). Cooler bulk ferment temperatures favour lactic acid production.
Crust is too hard / thick
Bake with steam (Dutch oven) for the first 20 minutes, this gelatinises the surface and creates a thin, crispy crust. Remove lid for the final 20 minutes to brown. If crust hardens as it cools, it's over-baked.
Dough spread flat when scored
Over-proofed (fermented too long). The gluten network has broken down and can't hold its shape. Next time, shorten bulk by 30-60 minutes or cold-retard sooner. Also check your shaping tension.
Starter smells like nail polish remover
It's hungry, acetone smell means the starter has exhausted its food. Feed immediately (1:2:2 ratio). This is common if you haven't fed it in several days. A few feeds will fix it.
Ear/bloom on the score is flat
Score deeper (¼ inch), at a sharper angle (almost horizontal), with a very sharp blade. Make sure the dough went into the oven cold (straight from the fridge) and the oven is fully preheated with the Dutch oven inside.
Related Cooking Tools
Pizza Dough Calculator
6 pizza styles with baker's percentages
Oven Temperature Converter
°F, °C, Gas Mark & Fan oven
Cups to Grams Converter
Accurate weights for 200+ ingredients
Baking Substitution Finder
Find ingredient swaps for baking
Recipe Scaler
Scale recipes up or down
All Cooking Tools
Browse all cooking & kitchen tools
How to use this tool
Set your desired number of loaves and target loaf size
Choose hydration level based on your preferred crumb style
Follow the timing plan, mix, bulk ferment, shape, cold proof, bake
Common uses
- Calculating exact flour, water, salt, and starter for sourdough
- Scaling a recipe to fit your Dutch oven or banneton
- Understanding baker's percentages for consistency
- Planning bake timings around your schedule
- Converting between UK strong bread flour and US bread flour by weight
Share this tool
Results are for general informational purposes only and should be checked before use. They are not professional advice. See our Disclaimer and Terms of Service.