Altitude Sickness Risk Calculator
Acute Mountain Sickness (AMS) is a real risk above ~3,500 m. Bhutan's trails cross 4,000–5,400 m routinely — Snowman Trek reaches 5,320 m, Jomolhari camp is 4,920 m. This calculator combines your trek's max altitude, ascent profile, age, and acclimatization days into a single AMS risk band with concrete mitigations.
Calculate risk
What this solves
Most generic "AMS prevention" pages give one rule for everyone ("climb high, sleep low"). This tool combines the actual variables: where you sleep, how fast you got there, your age (AMS susceptibility peaks 25–55), prior exposure, and whether you've planned Diamox. The output is a banded risk score, not a yes/no — because AMS is probabilistic.
How to read the result
- Low risk — below 3,500 m sleep altitude with 2+ acclimatization days. Headaches are possible but not life-threatening.
- Moderate risk — sleep 3,500–4,500 m. Add an acclimatization day. Carry Diamox 125 mg morning + evening prophylactically.
- High risk — sleep above 4,500 m or ascent rate over 500 m/day. Mandatory acclimatization day. Know the descent trigger (Lake Louise score ≥ 3 with headache = descend).
- Severe — Snowman / Lunana. Two acclimatization days minimum. Discuss with a trekking doctor before departure.
Limitations
- This is a risk bander, not a medical tool. Real AMS is individual — symptoms can show at 2,800 m for sensitive people.
- Pre-existing conditions (heart, lung, anemia, pregnancy) substantially shift risk. Consult a travel doctor.
- This tool does not know real-time trail conditions, weather, or your current fitness.
FAQ
When should I take Diamox?
Start 24 h before you sleep above 3,500 m. Typical prophylactic dose: 125 mg twice daily. Continue 48 h after acclimatization. Side effects: tingling in fingers / altered taste — both normal.
What's the descent trigger?
Persistent headache + Lake Louise AMS score ≥ 3 (out of 15) for 24 h → descend immediately. ≥ 500 m descent often resolves symptoms within hours.
Sources
- Lake Louise AMS Scoring System (International Society for Mountain Medicine)
- CDC Travelers' Health — Yellow Book, High-Altitude Travel
- Wilderness Medical Society Guidelines, AMS / HACE / HAPE