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Aviation Calculators

True Airspeed Calculator

True airspeed from indicated airspeed, pressure altitude and temperature.

Enter values

Results update as you type.

Result

True airspeed

123.7 knots

In km/h
229.1
In mph
142.3
Density altitude
6,226 ft
ISA temperature at this altitude
3.1 °C
ISA deviation
1.9 °C
Mach number
0.1903

A rule-of-thumb approximation — use your aircraft’s performance charts for operational decisions.

About the True Airspeed Calculator

True airspeed from indicated airspeed, pressure altitude and temperature.

Also known as: tas calculator, ias to tas, airspeed conversion, calibrated airspeed.

How to use this calculator

  1. Enter indicated airspeed, pressure altitude, outside air temperature.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

TAS ≈ IAS × (1 + 0.02 × density altitude in thousands of feet)

Worked example

Using the values pre-filled in the calculator above:

  • Indicated airspeed = 110 knots
  • Pressure altitude = 6,000 ft
  • Outside air temperature = 5 °C

the calculator returns:

  • True airspeed: 123.7 knots
  • In km/h: 229.1
  • In mph: 142.3
  • Density altitude: 6,226 ft