Turn calibrated airspeed into true airspeed for any altitude and temperature, with the density ratio and an approximate Mach number alongside.
Enter calibrated airspeed (use IAS if that is all you have), pressure altitude, and OAT. Leave OAT blank to assume ISA. TAS = CAS divided by the square root of the density ratio.
Enter CAS and a pressure altitude to see the true airspeed.
Thinner air at altitude means the same calibrated airspeed corresponds to a higher true airspeed — roughly 2% more per 1000 ft as a rough check.
σ combines the pressure and temperature ratios. TAS = CAS divided by the square root of σ.
Once you have TAS, the wind component calculator turns it into the runway and track picture you actually fly.
True airspeed equals calibrated airspeed divided by the square root of the density ratio. SkyStudy derives the density ratio from the pressure altitude and outside air temperature.
Enter IAS in place of CAS for a close estimate, and leave OAT blank to assume standard (ISA) temperature at the pressure altitude you enter.
It is the incompressible estimate — it ignores Mach compressibility, which matters at high speed and altitude. It is accurate enough for ATPL-level work and quick checks, not for primary navigation.
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