E6B Flight Computer: How to Use One and Which to Buy

The E6B flight computer is the FAA-legal tool that handles the core math of flight planning: groundspeed and time en route, fuel burn, true airspeed, wind correction angle, and density altitude. Every student pilot learns one, examiners expect you to demonstrate it, and it never loses signal or battery in the cockpit. This guide explains what an E6B does, how to use it, and how to choose between a manual slide-rule model, an electronic unit, and the plotter that completes your navigation kit.

Pilot Mall stocks mechanical E6Bs, electronic models, and VFR plotters from the brands instructors trust, ASA and Jeppesen. Browse them all in the flight computers and plotters collection.

What an E6B does

An E6B is a purpose-built aviation calculator with two sides. The circular slide-rule side handles multiplication and division problems: groundspeed and time en route, fuel burn and endurance, true airspeed from indicated, and density altitude. The wind side, a rotating grid, solves the wind triangle so you can find your wind correction angle and groundspeed for a planned heading. Together they let you build a complete VFR navigation log before you ever start the engine.

How to use an E6B

The calculator side works on ratios. Line up two known values on the inner and outer scales and read the answer under a third. A few examples you will use constantly:

• Groundspeed and time: set distance flown over time elapsed to find groundspeed, then read the time remaining for the distance left to run.
• Fuel burn: set your burn rate against the rate index to read total fuel for a leg, or endurance from the fuel aboard.
• True airspeed and density altitude: set pressure altitude against temperature in the airspeed window to correct indicated airspeed and read density altitude.

On the wind side, plot the wind, rotate the true course under the index, and read the wind correction angle and groundspeed directly. Most instructors have students master the manual unit first, because working the ratios by hand builds the understanding an electronic unit hides.

Manual, electronic, and plotters

Manual (mechanical) E6B

A manual slide-rule E6B never needs batteries, cannot fail on test day, and forces you to understand the relationships behind each answer, which is why most CFIs recommend a student own one first. The ASA E6B Paper Flight Computer is the low-cost entry point, while the aluminum ASA E6B and the Jeppesen Metal E6-B add durability that survives years in a flight bag. The round-window circular E6B is a compact alternative, and the ASA Color E6B improves readability.

Electronic E6B

An electronic E6B solves the same problems faster with fewer steps, which helps once you are flying real cross-countries. The ASA CX-3 Flight Computer is accepted on FAA knowledge tests and adds timer, clock, and unit-conversion functions.

Plotters

Pilotage and dead-reckoning planning need a plotter to measure course and distance on a sectional chart. The ASA Rotating Plotter pairs with any E6B to complete a VFR navigation-log workflow.

How to choose the right flight computer

• Start with a manual E6B. Examiners often expect you to demonstrate the manual unit, so most students buy a mechanical model first and add electronics later.
• Decide mechanical or electronic. Mechanical units are battery-free and inexpensive; electronic units like the CX-3 are faster and reduce steps on long cross-countries.
• Match the layout you train on. ASA and Jeppesen E6Bs read slightly differently, so pick the one your instructor and study materials use.
• Add a plotter. A rotating plotter completes the VFR planning kit and is needed for course and distance measurement on sectionals.

Compare the options

Frequently asked questions

Written by Neil Glazer, commercial pilot (multi-engine and instrument rated) and the team at Pilot Mall.