True Airspeed Calculator
Estimate true airspeed from indicated airspeed and altitude.
True airspeed exceeds indicated airspeed at altitude because the air is thinner.
The math behind it
A common rule of thumb adds about 2% per 1000 ft to the indicated airspeed.
Worked example
150 kn indicated at 8000 ft → about 174 kn true.
FAQ
Why does the airspeed indicator read low?
It measures dynamic pressure, which falls as air density drops.