What this calculator works out
Turns a set of bread ingredients into baker's percentages: hydration, salt and yeast as a proportion of the flour weight. It will also tell you how much water to use to hit a target hydration.
It counts the starter properly. A sourdough starter contains both flour and water, and both belong in the totals — forgetting that is the commonest reason a calculated hydration does not match how the dough actually feels in the hand.
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Before you calculate
- Every quantity is expressed as a percentage of the flour weight. Flour is always 100 per cent, whatever it weighs.
- Weigh everything, including the water. One millilitre of water weighs one gram, so a jug works, but scales are easier.
- Hydration is not a target to chase. Higher is not better; it is simply wetter, harder to handle and more open in the crumb.
Because they make recipes comparable and scalable regardless of batch size. A dough at 70 per cent hydration behaves the same whether you are making one loaf or fifty, and a baker reading "72 per cent, 2 per cent salt" knows immediately what the dough will feel like. It also makes scaling trivial: pick a flour weight and everything else follows.
How this calculator works
Baker's percentage = ingredient weight ÷ flour weight × 100
Hydration = total water ÷ total flour × 100Where a sourdough starter is used, it contains both flour and water, and both count towards the totals. A starter at 100 per cent hydration is half flour and half water by weight, so 200 g of starter adds 100 g to each side of the sum. Ignoring this is the most common reason a calculated hydration does not match how the dough actually feels.
Typical hydrations
| Bread | Hydration | Handling |
|---|---|---|
| Bagels, pretzels | 50 to 57% | Stiff, needs a strong mixer or hard work |
| Pizza, Neapolitan | 58 to 65% | Firm, easy to shape |
| Sandwich loaf, tin bread | 60 to 65% | Straightforward, tight even crumb |
| Baguette | 65 to 70% | Slightly slack but manageable |
| Sourdough, everyday | 70 to 78% | Sticky, needs folds rather than kneading |
| Ciabatta, focaccia | 75 to 85% | Very wet, handled with wet hands and a scraper |
Salt is normally 1.8 to 2.2 per cent of the flour weight. Below that, bread tastes flat; above it, fermentation slows noticeably. Instant yeast is usually 0.5 to 1.5 per cent depending on how long you want the rise to take.
Worked example
500 g flour, 325 g water, 10 g salt, 7 g instant yeast:
- Hydration: 325 ÷ 500 = 65%
- Salt: 10 ÷ 500 = 2%
- Yeast: 7 ÷ 500 = 1.4%
- Total dough weight: 842 g
That is a straightforward everyday loaf: firm enough to knead on a worktop, open enough to be pleasant. To take it to 70 per cent you would need 350 g of water, which is 25 g more and noticeably stickier.
Common mistakes
- Forgetting the flour and water in the starter. The single most common error in sourdough percentages.
- Chasing high hydration. A well-made 68 per cent loaf beats a badly handled 82 per cent one every time.
- Not adjusting for the flour. Wholemeal and strong flours absorb more water than plain white, so the same percentage feels drier.
- Measuring water by volume in a jug. Workable, but scales are more accurate and quicker.
- Counting oil, eggs or milk as water. They are separate percentages. Milk is roughly 87 per cent water if you want to be precise about enriched doughs.
- Increasing salt to slow a fast rise. Lower the yeast or the temperature instead.
Frequently asked questions
What is baker's percentage?
A way of expressing every ingredient as a percentage of the flour weight, with flour always counted as 100 per cent. It makes recipes scalable and comparable: a dough described as 70 per cent hydration with 2 per cent salt behaves the same whether you are making one loaf or fifty.
What hydration should I use?
It depends on the bread and on your confidence. Around 65 per cent for a straightforward tin loaf, 70 to 78 for everyday sourdough, and 75 to 85 for ciabatta or focaccia. Higher hydration gives a more open crumb but is harder to handle. If dough is sticking to everything and losing its shape, come down five per cent rather than fighting it.
Does the starter count towards hydration?
Yes, and forgetting it is the most common error. A starter at 100 per cent hydration is half flour and half water by weight, so 200 g of starter adds 100 g of flour and 100 g of water to the totals. Leave it out and your calculated hydration will be lower than the dough actually is.
Why does the same recipe feel different with different flour?
Absorption varies. Wholemeal, rye and strong bread flours take up more water than plain white, so the same percentage produces a firmer dough. Protein content and even the age of the flour make a difference. Treat a published hydration as a starting point for your flour rather than a fixed rule.
How much salt should I use?
Between 1.8 and 2.2 per cent of the flour weight, so 9 to 11 g per 500 g of flour. Below that the bread tastes noticeably flat. Above it, fermentation slows and the crumb tightens. Salt is one of the few percentages where the useful range really is narrow.
Do milk, eggs and oil count as liquid?
Not as water for the hydration figure — each is its own percentage. If you want to be precise about an enriched dough, milk is roughly 87 per cent water and eggs about 75 per cent, and those fractions can be added to the hydration. For everyday baking it is simpler to treat enriched doughs on their own terms.
Is what I enter stored?
No. Figures are processed in your browser and never transmitted or retained.
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References
These organisations publish the guidance and figures behind this page.
- Food Standards Agency — UK food safety guidance for home cooks and businesses
- NHS — why raw flour and raw dough should not be eaten, and safe handling in the kitchen
- British Standards Institution — standard metric measures used for flour and water in recipe scaling
Sources are checked at publication and can change — how I choose and check references.