Airspeed Calculator

Convert between IAS, TAS, CAS, and groundspeed — with density altitude corrections.

Calculator Aviation Updated Apr 19, 2026
Learn how this works
How to Use
  1. Enter IAS and pressure altitude.
  2. TAS is computed for the given temperature.
Inputs
Presets
Typical cruise altitudes — tap to set
Low / pattern work2,000 ft
Trainer cross-country6,000 ft
Piston high cruise9,000 ft
Turbocharged single12,000 ft
Turbo / oxygen FL17517,500 ft
Turboprop FL25025,000 ft
Speed ladder
kt true airspeed
IAS / CAS
TAS
TAS gain

Show Work

Enter values to see the step-by-step calculation.

Definitions

IAS
Indicated Airspeed — what the instrument reads
CAS
IAS corrected for instrument and position error
TAS
True airspeed — CAS corrected for density
GS
Ground speed — TAS ± wind component
Rule of thumb
TAS ≈ IAS × (1 + 0.02 · alt_kft)

About the Airspeed Calculator

Airspeed Calculator is a quick, free tool for flight planning and aircraft performance. It works in your browser and keeps everything on your device. Convert between IAS, TAS, CAS, and groundspeed — with density altitude corrections.

How it works

Enter your figures and the result appears instantly, updating the moment you change anything. There is no submit button and nothing to wait for, so it is easy to try a few what-if numbers and compare the results. Just check each box holds the kind of value it expects.

Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.

Frequently Asked Questions

How do I use the Airspeed Calculator?

Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.

Does it cost anything or need an account?

No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.

Is anything I type uploaded?

No. The tool works entirely on your device, so the values you enter never leave your browser.

Common Use Cases

Learn while you do it

Seeing what you put in and what comes out helps you understand how they fit together.

Get an answer fast

Type what you have and get the answer in seconds — on a phone, tablet, or computer.

Try different numbers

Change one thing and watch the answer change. It is an easy way to compare your choices.

Stays on your device

Your inputs never leave the browser — nothing is uploaded, logged, or stored anywhere.

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