Altitude Acclimatization Calculator
A safe ascent plan and altitude sickness risk.
Enter your values
Enter the starting sleeping altitude in m.
Enter the target sleeping altitude in m.
Enter the days you plan to take in days.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Your ascent rate
- 500 m per night
- Risk
- Low — within the 500 m guideline
- Recommended days
- 6 days including 2 rest days
- Total ascent
- 2,000 m
- Effective oxygen at target
- 55% of sea level
- Rest days needed
- 2
Quick answer
Above 3,000 m, sleep no more than 500 m higher each night and take a rest day every 1,000 m of ascent to reduce the risk of acute mountain sickness.
Safe days = (target − 3000) ÷ 500 + rest days
At a glance
| What it does | A safe ascent plan and altitude sickness risk. |
|---|---|
| Category | Travel |
| Inputs needed | Starting sleeping altitude, Target sleeping altitude, Days you plan to take |
| Main output | Your ascent rate |
| Formula | Safe days = (target − 3000) ÷ 500 + rest days |
| Cost | Free — no sign-up, no download |
How to use the Altitude Acclimatization Calculator
- 1Enter the altitude you are sleeping at now.
- 2Enter the highest altitude you will sleep at.
- 3Enter the days you have allowed, then compare with the recommendation.
Inputs explained
- Starting sleeping altitude(m)
- Enter the starting sleeping altitude in m.
- Target sleeping altitude(m)
- Enter the target sleeping altitude in m.
- Days you plan to take(days)
- Enter the days you plan to take in days.
Worked example
Using the values the calculator loads with:
Inputs
- Starting sleeping altitude2800 m
- Target sleeping altitude4800 m
- Days you plan to take4 days
Results
- Your ascent rate500 m per night
- RiskLow — within the 500 m guideline
- Recommended days6 days including 2 rest days
- Total ascent2,000 m
- Effective oxygen at target55% of sea level
- Rest days needed2
Frequently asked questions
What is 'climb high, sleep low'?
Ascending during the day and returning to a lower altitude to sleep speeds acclimatization without increasing overnight risk.
What are the warning signs?
Headache with nausea, dizziness or poor sleep is acute mountain sickness. Confusion, breathlessness at rest or a wet cough means descend immediately.
What do I need to enter into the Altitude Acclimatization Calculator?
Just 3 values: starting sleeping altitude, target sleeping altitude, days you plan to take. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Altitude Acclimatization Calculator work out the answer?
Above 3,000 m, sleep no more than 500 m higher each night and take a rest day every 1,000 m of ascent to reduce the risk of acute mountain sickness. It applies the formula Safe days = (target − 3000) ÷ 500 + rest days and shows the working so you can check each step by hand.
Is the Altitude Acclimatization Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.