liminfoE6B Flight Calculator
Free web tool: E6B Flight Calculator
Wind Correction Angle
-7.2°
Heading
353°
Ground Speed
119 kt
About E6B Flight Calculator
The E6B Flight Calculator is a free browser-based aviation tool that replicates the core wind triangle and density altitude computations of the classic E6B circular slide rule. It has two tabs: Wind Correction and Density Altitude. In the Wind Correction tab, you enter your True Airspeed (TAS) in knots, desired course in degrees, wind direction in degrees, and wind speed in knots. The calculator uses the sine rule to solve the wind triangle, computing the Wind Correction Angle (WCA), the corrected magnetic heading, and the resulting ground speed. Results update instantly as you type.
The Density Altitude tab solves for the actual air density experienced by an aircraft at a given airfield. You enter the field elevation in feet, the outside air temperature in degrees Celsius, and the current altimeter setting in inches of mercury. The calculator first derives Pressure Altitude using the standard correction of 1,000 ft per 1 inHg deviation from 29.92 inHg, then computes the ISA standard temperature at that elevation (15°C minus 2°C per 1,000 ft), and finally applies the density altitude formula: DA = Pressure Altitude + 120 × (OAT − ISA Temp). High density altitudes significantly reduce aircraft engine power and lift, making this calculation critical for safe takeoff performance planning.
This tool is designed for student pilots studying for the FAA Private Pilot written examination, flight instructors, and recreational VFR pilots who need a quick pre-flight planning check without carrying a physical E6B computer. All computation is done entirely in the browser using standard aviation formulas. The interface adapts to Korean and English and supports dark mode for use in low-light cockpit environments.
Key Features
- Wind triangle solver: computes Wind Correction Angle (WCA), corrected heading, and ground speed from TAS, course, wind direction, and wind speed
- Density altitude calculator: derives pressure altitude, ISA temperature, and density altitude from field elevation, OAT, and altimeter setting
- Uses standard aviation formulas identical to FAA-approved E6B computations
- Real-time updates — all outputs recalculate instantly as any input changes
- Handles both headwind and tailwind components automatically via the wind triangle sine rule
- Pressure altitude correction applies standard 1,000 ft per 1 inHg deviation from 29.92 inHg
- ISA temperature computed as 15°C − 2°C/1,000 ft, matching ICAO standard atmosphere
- 100% client-side — no data is sent to any server, suitable for pre-flight use without internet dependency
Frequently Asked Questions
What is Wind Correction Angle (WCA) and why does it matter?
Wind Correction Angle is the number of degrees left or right that a pilot must point the aircraft nose away from the desired course to compensate for crosswind drift. Without applying WCA, the aircraft will be blown off course by the wind even though the compass heading appears correct. The E6B calculator computes WCA using the formula WCA = arcsin(wind speed × sin(wind direction − course) / TAS).
How is ground speed calculated from TAS and wind?
Ground Speed (GS) is the actual speed of the aircraft over the ground. It equals TAS plus or minus the wind component along the flight path. The calculator solves the wind triangle: GS = TAS × cos(WCA) + wind speed × cos(wind direction − course). A headwind reduces ground speed below TAS; a tailwind increases it.
What is density altitude and why is it important for takeoff?
Density altitude is the pressure altitude corrected for non-standard temperature. It represents the altitude at which the air has the same density as the actual air the aircraft is operating in. High density altitude (hot, high, humid conditions) means thinner air, which reduces engine power output and decreases lift, requiring longer takeoff distances. On hot summer days at high-elevation airports, density altitude can exceed the field elevation by several thousand feet.
What is the ISA temperature and how is it calculated?
The International Standard Atmosphere (ISA) temperature is the expected temperature at a given altitude assuming standard conditions. It decreases at 2°C per 1,000 ft from a sea-level baseline of 15°C. So at 5,000 ft elevation, ISA temperature is 15 − (2 × 5) = 5°C. When the actual OAT is higher than ISA temp, density altitude is higher than pressure altitude, indicating reduced aircraft performance.
What inputs does the E6B wind correction calculator need?
You need four values: TAS (True Airspeed in knots), your desired course or track (degrees magnetic), wind direction (the direction the wind is blowing FROM, in degrees), and wind speed (knots). The calculator then outputs the Wind Correction Angle, the corrected heading to fly, and the resulting ground speed for flight time and fuel planning purposes.
How accurate is this calculator compared to a physical E6B?
This calculator uses the exact trigonometric sine-rule solution for the wind triangle, which is more precise than the graphical approximation of a physical E6B circular slide rule. The digital computation has no mechanical rounding error. For FAA written exam study, both approaches produce equivalent results within acceptable tolerances. For actual in-flight navigation, always verify with current winds-aloft forecasts.
Can I use this for IFR flight planning as well as VFR?
Yes. The wind correction angle and density altitude formulas are the same for IFR and VFR operations. IFR pilots typically compute these values through flight management systems or dispatch software, but this free calculator is useful for quick verification or when preparing for the IFR written examination. For actual IFR flights, always use certified avionics and approved navigation data.
What does it mean when density altitude is much higher than field elevation?
A large difference between density altitude and actual field elevation indicates the air is significantly warmer and/or less dense than standard atmosphere. For example, a 5,000 ft elevation airport on a 35°C day may have a density altitude of 8,000 ft or more. This means the aircraft will perform as if it were at 8,000 ft even though it is physically at 5,000 ft — requiring significantly longer takeoff roll and reduced climb rate. Always consult the aircraft POH performance charts using the computed density altitude.