Altitude Oxygen Calculator – Check Local O2 Levels Instantly

Whether you're at 800 feet or 8,000, your lungs deserve better than 21%

Or get elevation by city:

While the air is still 21% oxygen at that elevation, the reduced atmospheric pressure means there are fewer oxygen molecules in each breath compared to sea level. Learn more below.

Why Altitude Affects Oxygen Levels

As elevation increases, air pressure decreases—and with it, the availability of oxygen. At sea level, oxygen comprises about 20.9% of the atmosphere, but that percentage drops with each gain in altitude. This phenomenon is why you may feel out of breath hiking in the Rockies or skiing in the Alps. Understanding how much oxygen is available at your elevation is more than just curiosity—it's a game changer for energy, focus, and recovery.

The Math Behind the Oxygen Level Calculation

We use a scientific formula to estimate oxygen levels at your altitude. Here's how it works:

Oxygen % = 20.9 × (1 − 0.0000225577 × elevation)5.25588

Where:

20.9 is the percentage of oxygen in air at sea level
0.0000225577 is the lapse rate constant
elevation is your height in meters above sea level
The exponent 5.25588 adjusts for pressure change with altitude

This gives you a calculated oxygen concentration that reflects the reduced atmospheric pressure at higher elevations—so you know just how thin your air really is.

What Low Oxygen Does to Your Body

Feeling off at altitude? You're not imagining it. As oxygen levels fall, your body struggles to function optimally. Here are some common symptoms of mild hypoxia (low blood oxygen):

Fatigue and weakness
Shortness of breath during minimal activity
Headaches and dizziness
Brain fog or trouble concentrating
Delayed muscle recovery

Why REV/O2 Matters at Elevation

At elevations over 5,000 feet, you're breathing significantly less oxygen per breath. REV/O2 delivers 98% pure oxygen, bypassing the limitations of thin air to help you feel and perform your best. Whether you’re trail running, snowboarding, or just trying to acclimate, our portable oxygen cans give you control over how you breathe at altitude.

Use Cases for the Altitude Oxygen Calculator

Hikers and backpackers prepping for high-altitude treks
Seniors or individuals with respiratory issues planning mountain travel
Athletes training or competing at elevation
Outdoor enthusiasts looking to optimize recovery and energy

Try It, Breathe Easier — Use the calculator above to see how much oxygen you're really getting—and discover how REV/O2 can help fill the gap. It’s simple science that makes a noticeable difference.

High Up? Here’s the Lowdown on Oxygen (and this calculator).

How accurate is the oxygen percentage shown in this calculator?

We use the barometric formula and your elevation to estimate the oxygen content in the air. It's not lab-precision, but it’s scientifically grounded and gives you a solid sense of what your lungs are working with.

Why does altitude affect how much oxygen I get?

It’s not that there’s less oxygen in the air—it’s that there’s less air in the air. Higher altitudes mean lower atmospheric pressure, which means fewer oxygen molecules per breath.

What’s the normal oxygen level at sea level?

At sea level, air contains about 20.9% oxygen. The higher you go, the lower that number drops—which is why you may feel winded in the mountains.

Who should use this calculator?

Hikers, skiers, athletes, seniors, or anyone traveling to or living at higher elevations who wants to understand how altitude impacts their oxygen intake.

How does 98% Oxygen help with low oxygen at high altitude?

REV/O2 delivers 98% pure oxygen in a portable can. It bridges the gap between what your body needs and what the air at elevation actually provides—so you can breathe easier, recover faster, and feel better.