Altitude Adjustment

The atmospheric pressure calculator is supplied as part of the PowerCalc Cyclists Power Calculator

Atmospheric pressure at a given altitude (height above sea level) is calculated as follows:

Where:

p =	corrected pressure (mb)
p0 =	Pressure at sea level (normally about 1013mb)
y =	Altitude (metres above sea level)
R =	Gas constant, J/mole.K
M =	Molar mass of air
T =	Temperature (degrees Kelvin)
g =	Gravitational constant

The atmospheric pressure calculator has three pairs of text boxes to allow Altitude, Temperature, and Pressure at sea level to be varied independently.

On the right side of the window; the red 3D rotating cube represents the volume of a mole of air at STP. The black cube represents the volume that the same amount of air will occupy - this is the one that shrinks and grows as you adjust temperature and altitude. Below is the same thing represented numerically in litres. The volume of n moles of a gas is calculated as follows:

Below that appears the concentration of oxygen in grammes per litre. About 21% of the air you breath is oxygen, the remainder is about 78% Nitrogen, the remaining 1% is a variety of gasses. Only the oxygen content is important providing the remaining gasses are inert (like nitrogen). Not enough oxygen and you will die.

The 'Nitrogen tent equivalent' is the proportions of oxygen and nitrogen that mixed together at sea level will simulate the oxygen content of air at a given altitude.

Other Features Of The Bicycle Power Calculator

Pedal Thrust Calculator Resting Energy Requirement Calculator Drag Coefficient Calculator Ramp test / warm up aid Wind Chill Calculator Altitude Adjustments Bicycle Gear Calculator Compatibility Bicycle Crank Length Calculator

Turbo Trainer Support Graph Plotting Ability Oxygen Requirement Estimator Energy From Food Calculator Protein Requirement Calculator Body Mass Index Calculator Shoe Size Equivalence converter Standard and Non Standard Tyre Sizes