# Sourdough Calculator — Baker's Percentage

> Enter total flour, hydration, starter, and salt percentages — get exact grams to measure plus the starter's flour + water contribution, no surprises.

Live tool: https://lofttools.com/tools/cooking-tools/sourdough-calculator

Category: Cooking & Kitchen

## How it works

1. **Enter total flour** — Type the total flour weight for the recipe — this includes the flour already inside your starter.
2. **Set hydration, starter and salt** — Hydration is water as a percent of flour (70-80% is standard). Starter is the levain as a percent of flour (20% is typical). Salt is usually 2%.
3. **Read "Measure into the bowl"** — The top card shows the exact grams to weigh out — flour, water, starter and salt — plus the final dough weight.
4. **Check recipe totals if needed** — The second card breaks down total flour, total water, effective hydration, and how much flour / water your starter contributes — so the subtraction is never a surprise.

## FAQ

### Why is "Flour to add" less than "Total flour"?

Baker's percentages count everything in your recipe, including the flour that's already inside your starter. A 100%-hydration starter is 50% flour + 50% water by weight, so a 200 g starter contributes 100 g flour. To avoid double-counting, the calculator subtracts the starter's flour from the total — you only add the rest from the bag.

### What is baker's percentage?

Baker's percentage expresses each ingredient as a percentage of total flour weight. 1000 g total flour at 75% hydration means 750 g total water, and a 20% starter means the recipe uses 200 g of levain.

### What hydration should I use?

Country sourdough is typically 68-78%. Below 65% gives a dense sandwich crumb; 78-85% gives an open ciabatta-style crumb but is harder to handle; 85%+ is pizza / focaccia territory.

### My starter is not 100% hydration — does that matter?

Yes. Open the Advanced panel and set your starter hydration (50-60% for a stiff starter, 125-150% for a liquid levain). The calculator will split your starter's flour and water correctly.

### Can I copy the recipe?

Yes. The Copy recipe button sends the full formatted recipe (measurements + totals) to your clipboard.

### How does the bake-day timeline work?

Bulk fermentation, shape, proof and bake milestones are calculated as hour offsets from mix, assuming a 22 °C kitchen. Bulk shrinks as hydration rises — wetter doughs ferment faster because there is more free water for yeast activity. Use the timeline as a planner, not a strict schedule: starter strength, flour, and room temperature all shift the real numbers.

### What do the colored bar segments represent?

The composition bar shows the share each ingredient contributes to the final dough weight — flour (warm), water (cyan), starter (violet), salt (muted). It's a quick visual sanity check: flour should dominate, water should be about two-thirds of flour at 75% hydration, starter is a sliver, and salt barely registers.

## Privacy — what we do not do

This tool runs entirely in the browser via WebAssembly. Your file never reaches a Loft Tools server. Specifically:

- **No upload.** The file bytes load into the browser tab's memory and process on your own CPU. Open DevTools → Network and observe zero outbound requests carrying file data while Sourdough Calculator — Baker's Percentage runs.
- **No AI training on your file.** Loft does not train models. We could not train on a file we cannot see.
- **No content scanning.** No virus, copyright, or content-moderation pass against your file. The bytes are not accessible to us.
- **No server-side log of file contents, filenames, or EXIF metadata.** Cloudflare edge captures URL and truncated IP for abuse defense (standard CDN behaviour). Cloudflare Web Analytics records anonymous page hits, no cookies, no PII. Nothing about your file content reaches any log.
- **No retention.** Close the tab and the file leaves browser memory. No backups exist on our side because no copy ever existed on our side.
- **No account.** No email, no signup, no auth, no telemetry tied to you.
- **Offline-capable after first visit** (PWA). Once you've loaded a tool, it caches; later sessions work without internet. For high-sensitivity files, run the tool once online to warm the cache, then disconnect before processing.

Compare with upload-based services: each transmits your file to a processing server. Even over HTTPS, each has logs, retention windows, and subpoena exposure. Loft has none of these because the server architecture does not include your file.

## More

- All tools: https://lofttools.com/tools
- Category: https://lofttools.com/tools/cooking-tools
- LLM index: https://lofttools.com/llms.txt