Pressure at Altitude Calculator

Standard is 29.92 inHg / 1013.25 hPa.
Leave blank and the standard-day temperature for the altitude is used. Supplying a real OAT is what turns pressure altitude into density altitude.
Static pressure
1,013.250 hPa
Standard Atmosphere & Aerodynamics Calculator
Pressure altitude
1.2 ft
Pressure altitude
0.35 m
Density altitude
-0.0 ft
Static pressure
101,325.00 Pa
Static pressure
29.9213 inHg
Temperature used
15.000 degC
Air density
1.224978 kg/m3
Density ratio to sea level
1.000000
Speed of sound
340.297 m/s
True airspeed
250.00 kn
Mach number
0.3779
Dynamic pressure (q)
10,131.070 Pa
Pressure altitude by the 1000 ft/inHg rule
0 ft
Worked out from ICAO Doc 7488, Manual of the ICAO Standard Atmosphere (extended to 80 km) and 3 other sources.
For planning and study. Aircraft performance must be taken from the approved flight manual for the specific aircraft; the standard atmosphere describes a reference day, not the one you are flying in.

How this is worked out

3 steps
  1. ISA at 0 ft: T = 288.15 - 0.0065 x 0 = 288.15 K.
  2. p = 101325 x (1 - 0.0065 x 0 / 288.15)^5.255786 = 101325 Pa = 1013.25 hPa.
  3. rho = p / (R T) = 101325 / (287.058 x 288.15) = 1.224978 kg/m3.

Results are general information, not financial, tax, legal, medical or engineering advice.