Enter your planned altitude (in meters or feet), ascent rate, and number of days at each elevation to get your altitude sickness risk level. The calculator returns a risk score, risk category (Low / Moderate / High / Very High), and tailored acclimatization advice based on your itinerary.
Altitude Sickness Risk Score
--
Risk Category
--
Altitude Zone
--
Recommended Action
--
Acute Mountain Sickness (AMS) is a collection of symptoms — including headache, nausea, fatigue, and dizziness — that occur when you ascend to high altitude faster than your body can adapt. It typically begins above 2500 m (8200 ft) and becomes increasingly common above 3500 m. Symptoms usually appear within 6–12 hours of reaching a new altitude.
Most people start to notice mild symptoms above 2500 m (about 8200 ft). The risk increases significantly above 3500 m (11,500 ft), and severe forms like HACE (High Altitude Cerebral Edema) or HAPE (High Altitude Pulmonary Edema) become a concern above 4500 m. Individual susceptibility varies considerably regardless of fitness level.
Ascent rate is one of the strongest predictors of AMS. Gaining more than 500 m per day above 3000 m dramatically increases your risk. The standard guideline is to ascend no more than 300–500 m per day in sleeping altitude once you are above 3000 m, and to take a rest day every third day.
Yes — a prior history of AMS is the single strongest individual predictor of future episodes. If you have suffered from AMS before, you should plan a slower ascent, consider preventive medication such as acetazolamide (Diamox), and consult a travel health specialist before your trip.
Physical fitness has surprisingly little protective effect against AMS. Even elite athletes can suffer from altitude sickness. Fitness helps with general endurance at altitude but does not significantly improve your body's acclimatization response. Ascent rate and individual physiology matter much more.
'Climb high, sleep low' means you can ascend to a higher altitude during the day but should return to a lower altitude to sleep. This technique helps your body acclimatize more effectively, as the altitude at which you sleep has the greatest physiological impact. It is widely recommended for treks above 3000 m.
Acetazolamide (Diamox) is the most commonly used preventive medication for AMS. It works by stimulating faster and deeper breathing, which improves oxygenation. It must be prescribed by a doctor and started 1–2 days before ascent. Ibuprofen has also shown some preventive benefit for headache. Always discuss medication options with a travel health professional.
The most important rule is: do not ascend further if you have any AMS symptoms. Rest at your current altitude for 24 hours and see if symptoms improve. If symptoms worsen — especially confusion, loss of coordination, or severe shortness of breath — descend immediately, as these can indicate HACE or HAPE, which are life-threatening emergencies. Supplemental oxygen and descent are the primary treatments.