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Baker's percentages explained simply, with one loaf worked end to end

By BakePen Editorial · Last updated 26 Sep 2026 · 5 min read

Open a professional bread formula and nothing is in grams. Everything is a percentage, and the percentages add up to far more than a hundred, which looks like a misprint until somebody explains the trick: flour is always 100%, and every other ingredient is measured against the flour. Once that lands, the system stops being code and becomes the clearest way a recipe has ever been written.

This article explains the notation with one loaf worked completely — percentages to grams, grams back to percentages — and shows the two things the system does better than any other: resizing a formula without changing the bread, and spotting a broken recipe before it costs you a bake.

Flour is the anchor

In ordinary baking, percentages describe parts of a whole. In bread, they describe parts of the flour. A formula reading flour 100%, water 70%, salt 2%, instant yeast 1% contains no total and needs none: whatever amount of flour you choose, the other ingredients are those shares of it. A kilogram of flour takes 700 g of water, 20 g of salt, 10 g of yeast. Four hundred grams of flour takes 280, 8 and 4. The bread is identical; only the batch changed.

This is why bakers guard the ratios rather than the weights. Weights belong to one batch size and one tin. Percentages belong to the bread itself, and travel between bakeries, countries and centuries untouched.

Reading a formula like a baker

With the anchor in mind, a formula becomes a description you can evaluate at a glance. Water at 60% promises a firm dough, easy to shape; at 80%, a slack, open-crumb artisan style that needs confidence and a couche. Salt lives in a narrow, sacred band — 1.8% to 2.2% of flour in almost every sane loaf; a formula showing 3.5% salt is either a typo or a punishment. Instant yeast between 0.5% and 1.5% covers most schedules, the low end for slow, flavour-building ferments.

Enrichment reads the same way: sugar and fat at 5% each is a soft sandwich loaf; butter at 40% and eggs at 50% is brioche territory, and you know it before weighing anything. The percentages are the recipe's personality, stated in numbers.

Turning percentages into a batch

The arithmetic is one direction only: pick the flour weight, multiply. For a home batch of two loaves at 500 g of dough each, start from the total, not the flour: add the percentages (100 + 70 + 2 + 1 = 173), divide the target dough weight by that sum (1000 ÷ 173 ≈ 5.78), and that quotient times each percentage gives the grams — 578 g flour, 405 g water, 12 g salt, 6 g yeast. The calculator on this site does precisely this in the common case where the flour weight is chosen directly.

Work this way once and a small superpower arrives: any formula ever published becomes any size you need, including the size of the flour you happen to have left in the bag — weigh the bag's remainder, call it 100%, and build the loaf around it.

Turning grams back into percentages

The reverse direction is how you capture a recipe that exists only as weights — a grandmother's loaf, a bakery's offhand numbers. Divide each ingredient by the flour weight and multiply by a hundred. If her loaf used 600 g flour, 390 g water, 12 g salt, the formula is 65%, 2% — and now it can be made at 400 g of flour for a small tin or 2 kg for a bake sale, faithfully, forever.

It is also the diagnostic direction. Convert a failing recipe to percentages and its problems announce themselves in the standard ranges: hydration at 52% explains the doorstop; salt at 1.2% explains the blandness; yeast at 3% explains the rocket rise and collapse. Formulas rarely lie once they are speaking percentages.

One loaf, both languages

Rescuing a recipe written for a bakery

A celebrated bakery publishes its country loaf as percentages — 80% white flour, 20% wholemeal, 75% water, 2% salt, 20% starter — and no weights, because its bakers make 60 kg at a time. At home you want one 900 g loaf. Total the percentages (217), divide (900 ÷ 217 ≈ 4.15), multiply through: 332 g white flour, 83 g wholemeal, 311 g water, 8 g salt, 83 g starter. Ten minutes of arithmetic — or ten seconds in the percentage calculator — and the bakery's loaf fits your Dutch oven.

Common mistakes

Adding ingredient percentages to 100. In baker’s notation the total is meaningless and usually lands between 150 and 250. Forcing it to 100 rewrites the recipe into a different bread.

Taking percentages of the total dough weight. Water at 70% means 70% of the flour, never of the finished dough. The wrong base understates every ingredient and the loaf comes out tight and salty.

Counting starter as pure addition. A starter in a formula is flour and water too. Listing it as a line is fine for weighing; forgetting its halves when judging hydration is the error the hydration calculator exists to catch.

Questions, answered

Why is flour split into two percentages in some formulas?

Because the blend is the recipe: 80% white and 20% wholemeal tells you the flour mixture at any batch size. The parts still total 100.

Can I use baker’s percentages for cakes?

You can express any recipe that way, and some bakers do for scaling. Cake formulas are more often balanced by total weight and egg ratios, so the notation is less universal there.

What hydration should a beginner aim for?

Around 65% with strong white flour: supple, flavourful, and forgiving to shape. Move up two points at a time as confidence grows.

The short version

Baker's percentages look like a private language and behave like a public gift: five minutes of learning buys every bread formula ever written, at every size, with its faults visible before you preheat anything. Weigh your flour, think in shares of it, and recipes stop being instructions for one batch and become descriptions of bread.

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