Proofing Time Calculator
Recipes say "rise 2 hours" and quietly assume a warm kitchen. If yours is cooler — or you're cold-fermenting — here's what that time really becomes.
Common temperatures
| Environment | Typical temp | Speed vs 75°F |
|---|---|---|
| Fridge (cold ferment) | 39°F / 4°C | ~4× slower |
| Cool room | 62°F / 17°C | ~1.7× slower |
| Average kitchen | 70°F / 21°C | ~1.2× slower |
| Recipe default | 75°F / 24°C | baseline |
| Oven with light on | 82°F / 28°C | ~1.3× faster |
| Proofing box | 90°F / 32°C | ~1.8× faster |
How it works
Yeast and bacteria activity scales with temperature in a predictable way: as a working rule, fermentation doubles for every 17°F (9.4°C) warmer and halves for the same drop. So the adjusted time is recipe time × 2^((recipe temp − your temp) ÷ 17) in Fahrenheit. It's an approximation, not physics — dough is a living thing — but it gets you far closer than ignoring temperature entirely.
Always confirm by eye. The dough is ready when it has grown by the amount the recipe describes and springs back slowly from a gentle poke. The clock is a guide; the dough is the truth.
FAQ
Is this accurate for sourdough?
The same rule applies, but sourdough varies more with starter strength and inoculation. Treat the result as a starting estimate and watch the dough.
Can I leave dough out overnight?
In a cool room with a small amount of yeast, yes. In a warm kitchen with a full dose, it will over-proof and collapse — use the fridge instead.
What temperature should my dough be?
Most bread targets 75–78°F (24–26°C) after mixing. The dough temperature calculator tells you what water temperature gets you there.