Aviation calculators that show their working

30 free calculators for flight planning practice and study. Every one explains the method it uses, shows a worked example that has been checked against a reference, and says where the result stops being reliable.

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How the numbers are checked

Each calculator is built from a published formula, not from copying another website. The working is then verified three ways: against a worked example from a reference, against a boundary or error case, and against the same calculation done in different units.

Where a calculator uses a full physical model rather than the familiar cockpit rule of thumb, the page says so and shows how far apart the two answers are. Where a result rests on an assumption that is often untrue, such as still air in a glide, the page says that too.

Read the full method and checking process

A note on using these in the air

These are educational and planning aids. They are not approved for operational use and they cannot replace current official weather, your aircraft flight manual, or the rules that apply to your flight. No calculation on this site approves a flight.

Read the full aviation disclaimer