Sourdough Hydration Calculator
Dough hydration percent, total weight, and flour to water ratio for bread.
What it does
Hydration is the single number that predicts how dough will feel. Divide water weight by flour weight and a 500 g flour plus 350 g water dough reads 70%, tacky but trainable. The tool above runs that ratio with total dough weight beside it.
Baker math anchors everything to flour at 100%. Water at 70% of flour weight is 70% hydration, salt near 2% seasons without drying, and scaling becomes multiplication instead of guesswork. King Arthur baking guides work the same example: 750 g water over 1000 g flour is 75%.
Ranges map to breads. Bagels sit near 55 to 60% and shape stiff, sandwich loaves near 62 to 66% slice cleanly, country sourdough near 68 to 75% opens the crumb, and ciabatta past 75% pours more than it kneads. Whole grain flour drinks more, so it usually wants a few points extra.
Weigh both parts for repeatable loaves. Cups of flour swing 20% with packing while grams never do, and starters count too: a 100 g ripened starter at even feeding hides 50 g flour with 50 g water inside the totals.
How to use
- Pick metric (g) or imperial (oz).
- Weigh the flour going into the dough.
- Weigh the water, counting starter water if used.
- Read hydration first to predict handling.
- Read dough weight to pick the pan or basket.
Formula
- flour
- Total flour weight, the 100% anchor.
- water
- Total water weight including starter water.
- dough
- Flour plus water before salt and starter solids.
Salt, oil, and seeds sit outside hydration by convention even though they drink a little. Strict totals fold starter flour and water into both sides, which lifts quoted values a point or two.
Worked example
Example: 500 g flour, 350 g water
Metric defaults: flour 500 g, water 350 g.
- Divide: 350 / 500 = 0.70.
- Percent: 0.70 x 100 = 70%.
- Dough: 500 + 350 = 850 g.
- Ratio: 1 : 0.70 flour to water.
- Tool shows 70%, 850 g, 1 : 0.7.
Reference table
| Style | Range | Water |
|---|---|---|
| Bagels | 55 to 60% | 550 to 600 g |
| Sandwich, pizza | 62 to 66% | 620 to 660 g |
| Country sourdough | 68 to 75% | 680 to 750 g |
| Ciabatta, focaccia | 75 to 85% | 750 to 850 g |
Limits
- Flour and water only; enrichments ignored by convention.
- Flour thirst varies by protein and milling.
- Starter flour and water need adding for strict totals.
- Feel also follows time, salt, and temperature.
Common mistakes
- Measuring flour in cups instead of grams.
- Forgetting starter water inside the total.
- Chasing high hydration with weak flour.
- Adding all water upfront to thirsty whole grain.
- Reading salt percent as part of hydration.
Try it yourself
Quick checks. Answers sit tucked under each question.
1000 g flour, 700 g water?
700 / 1000 = 70%, dough 1700 g.
500 g flour, 325 g water?
325 / 500 = 65%, dough 825 g.
400 g flour, 300 g water?
300 / 400 = 75%, dough 700 g.
Questions
What is 70% hydration?
70 g water per 100 g flour, such as 350 with 500.
Does starter count?
Strictly yes: add its flour and water to both sides.
What hydration for beginners?
Near 65 to 68% with bread flour shapes with least drama.
Why is my dough soup at 75%?
Weak flour or full water upfront; hold back 5% next time.
Do ounces work the same?
Yes. Ratios cancel units: 12.35 over 17.64 is still 70%.
Is salt part of hydration?
No. Salt stays at about 2% of flour beside the ratio.