Baker's Percentages, Weight Over Cups, and Why This Calculator Exists

Okay, let's get real for a second. I used to bake from recipes that said things like "three and a half cups of bread flour, loosely scooped." And I kept getting different results. Same recipe, same oven, same hands — different loaf every single time. I thought I was the problem. Turns out, the cups were the problem.

Here's the thing about volume measurements: they are a polite fiction. A cup of flour that you spoon gently into the measuring cup weighs about 120 grams. A cup of flour that you scoop straight from the bag can weigh up to 165 grams. That's a 37% difference before you've even gotten to the water. In sourdough, where hydration percentage controls everything — how the dough feels, how it ferments, how it opens in the oven — that kind of variation is the entire ballgame.

So What Is a Baker's Percentage, Exactly?

It's one of those ideas that sounds fancy and bakery-professional until you actually understand it, at which point you wonder why home baking ever did things any other way. Here's the principle: flour is always 100%. Every other ingredient in the recipe is expressed as a percentage of the total flour weight. That's it. That's the whole system.

So if you have 900 grams of flour and 720 grams of water, your hydration is 80%. If you have 18 grams of salt, your salt percentage is 2%. If you have 180 grams of starter, that's 20%. These numbers travel with the recipe no matter how big or small you make it. Scale up to five loaves or down to one — the percentages stay the same. The ratios are the recipe. The weights are just the math.

This is why every professional baker thinks in percentages. It's not gatekeeping; it's genuinely the most useful way to understand what a recipe is doing. Once you know that 75% hydration makes a dough that's tacky but manageable, and 82% hydration makes a dough that flows like slow lava and requires a bench scraper and a lot of confidence, you can look at any recipe, read the percentages, and know exactly what you're walking into before you've touched a gram of flour.

How to Use the Recipe Scaler to Adapt Any Recipe

This is where the scaler up top earns its keep. Say you find a recipe online — a beautiful, crusty miche from some blog — and the base amounts are written for one loaf. You're feeding twelve people for Thanksgiving. You need four loaves. Normally, you'd multiply every number by four on a notepad and then squint at it hoping you didn't miss one. With the scaler, you punch in the base recipe, type "4" in the number of loaves field, and every ingredient scales instantly.

Or maybe you don't think in loaves — maybe you have a specific proofing basket that holds exactly 850 grams of dough, and you want to fill it perfectly. Use the target dough weight mode. Type in 850 grams, and the calculator back-calculates the exact flour, water, starter, and salt you need to hit that number without changing any of the ratios.

The Tartine-style defaults I pre-loaded — 900g flour, 720g water (80% hydration), 180g starter (20%), 18g salt (2%) — are a great jumping-off point for any open-crumb country loaf. But the tool works with whatever recipe you love. Plug in your grandmother's recipe, your favorite cookbook formula, or that one loaf you got obsessively right in February and want to recreate forever.

A Word on Hydration and Flour Type

One more thing worth knowing: baker's percentages are relative to your flour, and different flours absorb water differently. A high-protein bread flour can handle 78% hydration with composure. A lower-protein all-purpose flour at the same percentage is going to be considerably stickier. Whole wheat and rye absorb more water than white flour, which is why recipes that include them often call for slightly higher hydration or an autolysing rest to let the bran soak up what it needs before you start developing gluten.

None of this changes the math — the percentages are still the percentages. It just means that as you get more experienced, you'll start adjusting hydration based on how your specific flour behaves. The calculator gives you the numbers. Your hands, over time, give you the feel. They work together. That's the whole art of it.

Start with the defaults. Scale to your pan. Weigh everything. Bake the loaf. Then come back and adjust. That loop — number, scale, bake, adjust — is the entire education of a bread baker, and it's a lot more fun when the math doesn't slow you down.