Boiling eggs at high altitude
The physics, in one paragraph
Air pressure drops as you climb, and with it the boiling point of water: roughly 1 °C per 300 m of elevation. At 1,500 m your water boils at around 95 °C; at 3,000 m closer to 90 °C. Here's the part that matters for your egg: once water boils, it cannot get any hotter — every extra bit of heat goes into making steam, not into raising the temperature. So at altitude your egg is sitting in genuinely cooler water, and cooler water cooks more slowly. Below about 1,000 m the effect is small enough to ignore; above that, it becomes noticeable — and it grows with every additional metre.
How much time to add
There's no exact formula — pot, egg size and your stove all play a part — but this rule of thumb gets you very close: above roughly 1,000 m, add about 15–30 seconds per extra 300 m for soft and medium eggs, and somewhat more for hard eggs, which spend longer in the too-cool water. Starting from the standard times for a size-M egg straight from the fridge, that works out roughly like this:
| Elevation | Soft (base 5:00) | Medium (base 7:00) | Hard (base 10:00) |
|---|---|---|---|
| Up to ~1,000 m | 5:00 | 7:00 | 10:00 |
| ~1,500 m | + about 30–50 s | + about 30–50 s | + about 1 min |
| ~2,000 m | + about 1–1½ min | + about 1–1½ min | + about 1½–2 min |
| ~2,500 m and up | + about 1½–2½ min | + about 1½–2½ min | + 2 min or more — test once |
Treat these as starting points, not gospel. Boil one test egg at your adjusted time, check it, and nudge from there.
What doesn't help
The instinctive fix — cranking up the heat — does nothing. A furious boil is exactly as hot as a steady one; the extra energy just evaporates your water faster and knocks the eggs around, which cracks shells. Adding salt to "raise the boiling point" is equally futile at kitchen quantities: the effect is a fraction of a degree.
The only lever you actually have is time. Water at 93 °C cooks an egg perfectly well — it just needs longer to do it. Everything else about your technique stays the same: water at a rolling boil, egg straight from the fridge, lowered in with a spoon, timer started immediately.
Dial it in once, keep it forever
The nice thing about altitude is that yours doesn't change. Unlike egg size or starting temperature, which vary carton to carton, your elevation is a constant — so once you've found the time that produces your perfect egg at your place, that time is settled. Spend one morning testing: start with the rule of thumb, check the result, adjust by 15 or 30 seconds, done.
This is exactly what custom times in Egg Timer are for. Every preset — each doneness level, on stove, induction or egg cooker — can be adjusted in 15-second steps from 2:00 to 30:00, as a one-time purchase with no subscription. Set your altitude-corrected times once, and every egg after that is just: pick, start, eat.
Your altitude, your times
With Egg Timer Pro you adjust every doneness level in 15-second steps — a one-time purchase, no subscription. Find your altitude-corrected time once, and the app remembers it forever.
Coming soon to the App Store