Bread Proofing Time Estimator
A recipe's proof time only applies at the temperature it was written for — here's roughly how much a warmer or cooler kitchen changes it.
The rule of thumb behind this estimate
Yeast fermentation roughly doubles in speed for every 17°F (about 10°C) increase in temperature, and roughly halves for the same drop — so this estimate scales the recipe's proof time by 2 raised to the power of (reference temp − your temp) ÷ 17. It's a widely used baking heuristic, not an exact physical law, but it gets you in the right neighborhood.
Why a cooler kitchen isn't just "a bit slower"
Because the relationship is exponential, not linear, a dough at 65°F instead of a recipe's 75°F reference isn't proofing 10% slower — it's taking meaningfully longer, often close to 50% more time. This is exactly why a dough left out overnight in a cool kitchen can go from "under-proofed" to "way over-proofed" faster than it seems like it should.
Cold retarding in the fridge doesn't follow the same curve
Near-freezing refrigerator temperatures slow yeast activity so much that it behaves more like a near-dormant pause than a predictable extension of this doubling rule — a dough retarded overnight in the fridge is more about flavor development through slow fermentation than a number you can calculate this way. Use the poke test (press a finger in; it should slowly spring back partway) as the real final check, not the clock alone.