Baker’s Percentages: The One Baking “Rule” That Actually Makes Sense

Ask a home baker what scares them off a “real” recipe, and most won’t say kneading, or proofing, or even sourdough starters. They’ll say percentages. Numbers next to ingredients instead of cups and spoons, as if baking bread suddenly demands a maths degree.

It doesn’t. Once it clicks, baker’s percentages are the easiest thing about baking. Easier than judging whether dough has “doubled in size.” Easier than converting cups to grams. You just have to see the trick once. So let’s see it.

Flour is always 100%

Here’s the whole rule: flour is always 100%, and every other ingredient is expressed as a percentage of the flour weight, not of the total dough, just the flour.

That’s it. That’s the rule bakers make sound complicated.

Say a recipe uses 1000g of flour and 700g of water. Water isn’t “70% of the dough.” It’s 70% of the flour. Add 20g of salt, and salt is 2%. Add 3g of instant yeast, and that’s 0.3%. Nobody’s dividing by the total weight of everything in the bowl. Everything is just compared back to one number: the flour.

Once you see it laid out like that, the “intimidating” recipe with all its percentages is really just a recipe that tells you exactly what it’s doing, instead of hiding behind “1 cup of this, a pinch of that.”

Where it actually clicked

For a while, I assumed the percentages had to add up to 100%, like a pie chart: flour, water, salt, yeast, all sharing one pot. During training, it turned out that’s not how it works at all. Every ingredient is compared to the flour, and only the flour. Add them all up and you’ll usually land somewhere north of 100%, and that’s fine, because the total was never the point. The question was always: how much of this, compared to how much flour?

The ingredient that trips people up first is water, mostly because we’re used to measuring liquids in litres, not grams.

Small aside: a litre of water weighs the same on your scale whether you’re at sea level or halfway up a mountain — that part never changes. What does change at altitude is how it behaves in the oven: lower air pressure means water boils at a lower temperature, so dough ferments and bakes differently the higher up you go. A pressure cooker does the same trick in reverse. Trap the steam, raise the pressure, and water boils hotter instead of cooler, which is why it cooks food faster. Same principle, opposite direction.

Why this beats guessing

Before any of this clicked, I’d bake batches of wildly different sizes: twenty dough balls for a weekend, six just to test a new flour, thirty for a bigger job. Every single time, the dough came out just a little different. Not ruined, just… not quite the same as last time. I put it down to feel, to the weather, to just being an inconsistent baker.

If pizza is your thing, the Pizza Dough Calculator does exactly this backward math: number of balls in, exact grams out.

It wasn’t any of that. It was that I was scaling by guesswork instead of by percentage. The moment you work in baker’s percentages, batch size stops mattering: 20 balls or 6 or 30, the ratios stay identical, so the dough does too. That’s the real payoff — not the maths itself, but what it lets you do.

With percentages, you can take a recipe you love at 1000g of flour and make it work at 250g or at 10kg, without touching the ratios. You can compare two completely different recipes at a glance, a 60% hydration loaf and a 75% hydration ciabatta, and know instantly which one will feel stiffer in your hands before you’ve even mixed either. And when something goes wrong, percentages tell you what went wrong: too little salt, too much water, not enough yeast, rather than a vague “I don’t know, I just followed the recipe.”

It’s also why professional bakeries never measure in cups. Volume is inconsistent: a “cup of flour” can vary by dozens of grams depending on how it’s scooped. Weight, expressed as a percentage of flour, is the same recipe every single time, whether you’re making one loaf or two hundred, bread dough or pizza dough.

Try it yourself

You don’t need to do any of this math by hand. Plug your own numbers into the Baker Calculator and watch the percentages update as you adjust ingredients: the same 1000g / 700g / 20g / 3g example from earlier, or your own recipe.

And once percentages make sense, a few things get a lot easier: figuring out what hydration to aim for depending on the bread you’re making, scaling a recipe up or down without losing your mind, and working out when to start that dough so it’s ready exactly when you need it.

Once this rule clicks, you stop measuring dough and start reading it. Next up: the smallest number in the recipe, and the one that does more work than you’d think. Read about salt in bread dough.

— Rob