As you go higher in the atmosphere, air pressure decreases because there is less air above you and the air becomes less dense.

Quick Scoop

  • Atmospheric (air) pressure gets lower with increasing altitude.
  • Most of the atmosphere’s mass is packed near the ground, squeezed by gravity, so pressure falls quickly at first and then more slowly the higher you go.
  • Higher up, air molecules are farther apart (lower density), so they collide less and push less on surfaces, which is what we measure as pressure.
  • By around 5–6 km (typical jet cruising heights are even higher), the pressure is already less than half of what it is at sea level.

A simple way to picture it

Imagine you’re at the bottom of a swimming pool: there’s a lot of water above you, so the pressure is high. Climb toward the surface and there’s less water above you, so the pressure drops. The atmosphere works the same way, but with air instead of water—climb a mountain or fly in a plane and there’s simply less air stacked above you, so the pressure goes down.

In short: as you go higher in the atmosphere, air pressure steadily drops because there is less overlying air and the remaining air is less dense.

Information gathered from public forums or data available on the internet and portrayed here.