What this solves
AMS risk is not a single number — it is a function of where you sleep, how fast you got there, and who you are. Most "altitude calculators" only ask elevation. This one weights four real factors from trekker cohort studies and pushes the result into a decision band, so you can plan an extra acclimatisation day before you fly to Daocheng.
Build your risk profile
risk = 12 + 0.022 × sleep_alt − 3.2 × days × max(0,1 − sleep_alt/6000) × history × profile_multiplier, clipped to 0–100.How to read the result
LOW (0–25) — Standard itinerary. One rest day at Yading village (3,700 m) before pushing to Luorong (4,080 m) is enough for most healthy adults.
MODERATE (26–50) — Add an acclimatisation day. Sleep two nights at Luorong Pasture (4,080 m) before any Milk Lake / Five-Colour Lake push. Consider Diamox 125 mg twice daily from 24 h before ascent.
HIGH (51–75) — Re-plan. Either insert a Shangri-La pre-acclimatisation day (3,300 m) before flying into Daocheng, or drop the Tanggu La (5,900 m) push-camp option. Descend if symptoms appear.
EXTREME (76–100) — Do not attempt the full traverse as planned. A prior HACE or HAPE history at this sleep altitude is a strong reason to switch to the inner Kora only.
Limitations
FAQ
A: Diamox (acetazolamide) shaves roughly 30 % off AMS incidence at 3,500–4,500 m, but it doesn't eliminate it. A 40 means "go, but add a day, and turn around the moment a headache scores ≥ 2."
A: Yes. Daocheng (3,750 m) and Yading village (3,700 m) are effectively the same altitude physiologically — both are above the 3,500 m AMS line.
A: Fitness correlates poorly with AMS. Ventilatory response to hypoxia — which you cannot train in a gym — is what matters. Fit people still get HAPE.
A: Most parties day-trip Tanggu La from a 4,400–4,800 m base, never sleeping above 4,800 m. That strategy keeps the risk score in the moderate band — entering 5,900 m as your sleep altitude is a different trip.