Baker's Percentage: Convert Any Recipe (With Calculator)

📖 8 min read · Updated July 2026

By SourdoughCalc Team

Baker's percentage is the universal language of bread. Every professional bakery in the world uses it. Once you understand it, you can read any bread recipe from any country, scale it to any loaf size, and adjust hydration to your exact flour. This guide gives you everything you need in 8 minutes.

The Basic Concept

Every ingredient in bread is expressed as a percentage of the flour weight, which is always 100%. Water at 70% means 70g of water for every 100g of flour. Salt at 2% means 2g of salt for every 100g of flour. This makes recipes infinitely scalable. To make a 500g loaf or a 5kg loaf, you change the flour and the math does the rest.

A Real Example

A standard sourdough boule uses 100% flour, 75% water, 20% starter, 2% salt. For a 500g flour batch, that translates to:

• Flour: 500g
• Water: 375g (75% of 500)
• Starter: 100g (20% of 500)
• Salt: 10g (2% of 500)
• Total dough: 985g

For a 1000g flour batch, just double everything. For a 300g flour batch, halve it. The ratios stay identical.

How to Convert Any Recipe

Most home recipes give ingredients in grams or cups. To convert to baker's percentage, follow these 3 steps:

1. Convert all ingredients to grams. 1 cup of flour is roughly 120g, water is 240g, salt is 5g per teaspoon.
2. Pick the flour weight as your baseline (100% = flour grams).
3. Divide every other ingredient's weight by the flour weight, then multiply by 100.

Example: a recipe has 400g flour, 300g water, 8g salt. Water is 300/400 = 75%. Salt is 8/400 = 2%. That is a 75% hydration recipe with 2% salt. Clean and unambiguous.

Why This Matters

When you read a recipe as percentages, the recipe reveals its character. A 65% hydration is a tight, chewy dough. 80% is slack and open-crumbed. 1.8% salt is mild. 2.2% is pronounced. Volume, hydration, crumb, color, and shelf life all follow from these numbers. You stop following recipes blindly and start understanding them.

Common Conversions (home baker ranges)

• Hydration: 60% (bagels, pretzels) → 75% (standard sourdough) → 85% (open crumb ciabatta)
• Salt: 1.8% (mild) → 2.0% (standard) → 2.5% (pronounced, longer fermentation)
• Starter: 10% (younger, faster) → 20% (standard sourdough) → 30% (longer fermentation, more sour)
• Hydration (whole grain): Add 5% to your base. Whole wheat absorbs more water.

Scale Any Recipe

Once you have the percentages, scaling is free. Want 1.5kg of dough for a large family loaf? Find your desired total, subtract the salt and starter, and the rest is flour + water in your preferred ratio. Or use our hydration calculator: enter the flour weight, your hydration percentage, and starter percentage, and the calculator gives you the exact gram amounts in one click.

Why Bakers Use Percentages

Percentages make recipes portable, comparable, and easy to adjust. A European rye recipe and an American sourdough recipe can be compared side by side in percentages even if the original gram amounts are wildly different. Once you read in percentages, you can adapt any recipe to your flour, your climate, and your schedule. Professional bakers don't even think in grams; they think in baker's percentage and only convert to grams when they actually mix.

A Quick Reference Cheat Sheet

Most home sourdough recipes live in a small range:

• Flour 100% (your baseline)
• Water 70-78% (hydration)
• Starter (active, ripe) 20%
• Salt 2%
• Optional: 5-10% whole grain for flavor

Total hydration (water + flour-water in starter) typically lands 72-80%. Start at 75% and adjust up or down by 2-3% per bake until you find what you love.

Put It Into Practice

Open any sourdough recipe online, convert it to baker's percentage in your head, and you'll quickly see what makes it tick. A 70% hydration sandwich loaf and an 80% ciabatta will look totally different to you than they did yesterday. Once percentages become intuitive, you can design your own breads from scratch.

Want to actually bake something with your new percentages? See our 24-hour sourdough schedule for a guided day-by-day plan.